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Author Topic: Blowing fuses - replace or repair?  (Read 12462 times)

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windmill

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Blowing fuses - replace or repair?
« on: May 20, 2011, 04:40:32 pm »
I bought a custom multicade from a company (via the web) with less-than-stellar service. After going back and forth for many months the owner told me he wasn't going to fix it, so I'm on my own.

The monitor (a 25" CRT) was essentially DOA. I turned on the machine, the monitor showed a brief sign of life (a lightened band visible for a couple of seconds), then went dark. I looked at the chassis (Wei-Ya 825H4) and noticed both fuses were blown. I got a replacement chassis from the company, installed it, powered up: Same problem, blown fuses.

Diagnosing/ repairing this myself would be ambitious. I know how to use a multimeter and I can solder up a couple of wires when I'm feeling brave, but that's about it. There is a custom arcade company here locally that also does repairs. It will cost ~$150 to get it to and from the shop, then there's labor and parts to consider. Best case it's something simple and I'm done for $300, worst case the tube itself must be replaced and the chassis is fried, and we're talking big bucks.  Alternatively, I can get a WG 26" LCD replacement kit (with brackets & bezel) for ~$600 shipped. The installation appears to be relatively straightforward, certainly something I can handle.

I'm looking for some advice on what you think my best option is. If based on these symptoms you're pretty sure the guy just has to resolder a new $30 flux capacitor and drain the gravitons from the positron emitter, I'm willing to roll the dice. If on the other hand you think it's likely I need at least two new $60 bazookoids and a plasma conduit for $150, I'd rather go the replacement route. And if you think cost-wise it'll be a wash I'll just flip a coin...  :lol

Thanks.


Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #1 on: May 21, 2011, 12:09:03 pm »
I assume your chassis is laid out like this one ? (both fuses side by side)

Since BOTH chassis did the same thing -
1. Check that there are no shorts in the power source feeding the monitor.
2. Check that there are no other devices (ie marquee light) tied into that power source and are shorted.
3. Unplug the degauss coil and see if it still blows the fuses. (two pin connector right by the fuses)

Did you EVER see this machine working with this model chassis in it ?
« Last Edit: May 21, 2011, 03:06:00 pm by Kevin Mullins »
Not a technician . . . . just a DIY'er.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #2 on: May 21, 2011, 02:29:48 pm »
Thanks for the reply.

I assume your chassis is laid out like this one ? (both fuses side by side) Yes, the fuses are side by side

1. Check that there are no shorts in the power source feeding the monitor. Check - no shorts.
2. Check that there are no other devices (ie marquee light) tied into that power source and are shorted. The monitor is the only thing tied into the power source.
3. Unplug the degauss coil and see if it still blows the fuses. (two pin connector right by the fuses) I unplugged the coil, powered up, but the 6A fuse still blew. The 2A fuse was still intact though. In the spirit of investigation, I put in another 6A fuse, plugged in the degauss coil, and powered up again. The 6A fuse blew as expected (a little more violently this time), the 2A fuse still remained intact. So I'm not sure why the 2A fuse blew previously.

Also, I don't know if this matters, but the monitor chassis is not grounded. The power plug is a 3 prong with ground, but the ground only goes to the PC board power supply, not to the chassis.

Did you EVER see this machine working with this model chassis in it ? No, I've never seen it working. But, I have to believe that the guy that built it at least selected compatible components. It's not cheap to ship these machines, so I assume he at least powered them up in his shop to make sure they worked. Granted, I'm not overly confident in the quality of the components he uses. The first machine he sent (yes, this is a very long and sordid story) had a faulty power supply.

Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #3 on: May 21, 2011, 03:15:13 pm »
Is the monitor being powered from an ISOLATION transformer ?

Post up a pic of where your monitor gets it's power if you are not sure.
or
Unplug the power cord going to the monitor and use your multimeter to check continuity between those pins and the cord end that plugs into the wall. There should be NO continuity on the two AC lines. (only the ground if it is complete)

Also, I don't know if this matters, but the monitor chassis is not grounded. The power plug is a 3 prong with ground, but the ground only goes to the PC board power supply, not to the chassis.

There should be a ground going to the metal "frame" of the monitor somewhere.
Shouldn't cause any blowing fuses, but should be there for shock hazard safety.
Not a technician . . . . just a DIY'er.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #4 on: May 21, 2011, 05:45:54 pm »
I hope this is helpful. Power goes to the switch, from there through standard 110V fuses (hot/ neutral) and then splits to the power supply for the PC board and the chassis.



Picture of the power supply and PC board



Shot of the chassis. The AC power comes in on the left side. As for what happens within the chassis...this is where we go from electrical to electronics I'm not sure what to look for.



Shot of the chassis and tube



So...are you saying there should be an isolation transformer go between the AC power and chassis? If so, I may just drive across a few state lines and pay the guy that built it a visit...even at $4/ gallon....


Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #5 on: May 21, 2011, 06:56:24 pm »
So...are you saying there should be an isolation transformer go between the AC power and chassis?

Yes, that is exactly what I'm saying......

AC power in----> Cabinet Fuse Block----> Isolation Transformer----> Monitor Chassis

The game pcb power can still come straight off the fuse block, just the monitor needs to be fed from the isolation transformer.

Many of the newer aftermarket monitor chassis do not require an iso, but that one does.
Hard to say if anything else has popped on the chassis though, might get lucky and the fuses actually saved everything. One way to find out without really going over the chassis electronics....put an iso in there and fire it up.

Would you happen to have one handy ?
Pretty straight forward installation if you have/get one.
Not a technician . . . . just a DIY'er.

lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #6 on: May 22, 2011, 12:21:42 am »
THAT is absolutely bizzare!  :dizzy:

if you wouldn't mind divulging the company/individual you got this from so the rest of us can avoid them...

you'd think that the builder(s) would know that this chassis needs an isolation transformer

a few questions come to mind...

for one... don't they test their stuff before they send it out?
and two... if they are experienced? how is it that they could make such a rookie mistake!!

i'm wondering if they had an isolation transformer that the whole machine was plugged into for testing... maybe it DID work when it left. but because there is no iso at your house POW! done like disco.

i would call and ask them. i would also tell them if they are using an iso as I have described for testing...uhm... to stop! and, and AAAAAND! send you another chassis, cause certainly there is a bunch of stuff fried on it. you paid (presumably) good money for an item that doesn't work due to a stupid mistake on THEIR part.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #7 on: May 22, 2011, 10:18:31 am »
if you wouldn't mind divulging the company/individual you got this from so the rest of us can avoid them...
I purchased the machine from Next Generation Arcades, in Gettysburg PA. The company is owned by Guy Minthorne. If you Google the company name you'll find the (very obvious) URL, but I'm not going to hotlink it here.

for one... don't they test their stuff before they send it out?
and two... if they are experienced? how is it that they could make such a rookie mistake!!
You know, I wonder that myself now. The first machine he shipped arrived two months late. For some reason, the shipping company took it to the wrong state. When it finally arrived, the sound didn't work. After swapping PC boards, the sound still didn't work, and the problem was ultimately traced to a faulty power supply. Is that something that should have been caught testing? Perhaps. I initially wrote it off as something that happened because the machine was in transit so long. I mean, who knows what can happen in a shipping dock, right? But, having just learned he didn't put in an isolation transfomer, I'm seriously starting to question the amount of testing he does on these machines.


windmill

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Re: Blowing fuses - replace or repair?
« Reply #8 on: May 22, 2011, 10:29:37 am »
Hard to say if anything else has popped on the chassis though, might get lucky and the fuses actually saved everything. One way to find out without really going over the chassis electronics....put an iso in there and fire it up.

Would you happen to have one handy ?
Pretty straight forward installation if you have/get one.
First let me say I really appreciate the diagnostics, this has been incredibly helpful. Unfortunately, I don't have an isolation transformer, but I have a feeling I'm going to buy one very soon...  ;D I hope the chassis has survived the onslaught of hooking it directly to 120VAC. I do still have the other chassis, so with a bit of luck at least one still works.

Would you have a recommendation on an iso supplier? I did a quick search on eBay and found a coupe of likely candidates, but other searches turn up a lot of industrial suppliers.  I have a feeling I'm going to get sucked into this hobby  :lol, so I might as well get started on my vendor list.




Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #9 on: May 22, 2011, 01:01:42 pm »
Bob Roberts carries them. http://www.therealbobroberts.net/ordering.html
He only accepts checks, money orders, etc.....he's a bit old school like that.
Just shoot him an e-mail, tell him what you need (Qty 1 - Isolation Xformer 1:1   $12.00), he'll tell you where to send the money, you drop payment in the mail, he sends you the part.

There's plenty of other places to get one, but I personally like recommending Bob first.

Happ Controls will ALWAYS be more expensive on everything.
http://www.happcontrols.com/powersupplies/80210000.htm
But someone like http://arcadeemulator.net/ who is a distributor for them could possibly cut you a better deal on the same part, just shoot him a message. (he's a local to me)


Not a technician . . . . just a DIY'er.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #10 on: May 22, 2011, 08:29:49 pm »
Bob Roberts carries them. http://www.therealbobroberts.net/ordering.html
He only accepts checks, money orders, etc.....he's a bit old school like that.
Thanks Kevin. Bob may be "old school" but he replies in "web time". Part ordered and check mailed. Until then... To Be Continued.

(keeping fingers crossed chassis still works)

Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #11 on: May 22, 2011, 09:56:21 pm »
Please do come back and update us.
I'm sure we can help if you have further issues.
Not a technician . . . . just a DIY'er.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #12 on: May 26, 2011, 01:51:12 pm »
Well, Bob rocks. Sent the order Sunday evening, part arrived by mail today (Thursday). Can't beat that!

I'll see about soldering it in this evening. Question: Should I ground the metal enclosure of the isolation transformer?


lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #13 on: May 26, 2011, 05:47:39 pm »
Can't hurt!

windmill

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Re: Blowing fuses - replace or repair?
« Reply #14 on: May 26, 2011, 07:19:05 pm »
OK, I officially still stink at Galaga. How do I know this? BECAUSE I JUST PLAYED MY FIRST GAME!!!  :cheers:
Clipped some wires, soldered in the iso, replaced the fuse, crossed my fingers and it came right up.  A big thank you to everyone who replied, especially Kevin.  :notworthy:

All is not perfect yet. I fiddled with the controls to get the picture width and brightness correct, but the picture is still too tall. I can do some adjustments with the vertical size, but not enough. A bigger concern is that the screen is wavy. It's like the CRT is an aquarium with the water slowly bobbing from right to left. Is that an indication the tube is bad or I partially fried the chassis? I can try the other chassis I have, but of course I'm hoping someone here will post "Not to worry my friend, simply turn the Foo in the direction of the Bar and it will straighten out".

(Yes, researching this stuff on the web too, but you know, there's not a lot of info on parts made before 1996...)

Anyway, ECSTATIC I've gotten this far with the simple inclusion of the iso. Although I'm still shaking my head that it wasn't included in the first place.  :dizzy:

lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #15 on: May 26, 2011, 07:52:34 pm »
Quote
It's like the CRT is an aquarium with the water slowly bobbing from right to left.

first off check that the degauss coil isn't causing it... you can safely unplug it to see. other than that...
make sure all the grounds are good... also check that the video wires are nice and tight.

Quote
Anyway, ECSTATIC I've gotten this far with the simple inclusion of the iso. Although I'm still shaking my head that it wasn't included in the first place.  

i'd send them a bill for the iso and your time.

EDIT: attached photo
« Last Edit: May 26, 2011, 08:23:48 pm by lilshawn »

windmill

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Re: Blowing fuses - replace or repair?
« Reply #16 on: May 27, 2011, 01:26:00 pm »
first off check that the degauss coil isn't causing it... you can safely unplug it to see. other than that...
make sure all the grounds are good... also check that the video wires are nice and tight.
Thanks for the suggestion. I checked the connections and unplugged the degauss coil, but that didn't really make much of a difference. This weekend I'll hook up the first chassis, see if that one does any better. I suspect that the replacement chassis I was sent was an older/ used one, so I'm still mildly optimistic I can get the picture to an acceptable level. If not, I guess I'll be looking at learning how to solder and replacing the capacitors. Of course, a great excuse to buy more tools and build a nice soldering station...  :tool:

Quote
Anyway, ECSTATIC I've gotten this far with the simple inclusion of the iso. Although I'm still shaking my head that it wasn't included in the first place.  
i'd send them a bill for the iso and your time.
I've already filed a complaint with the BBB and I'm contemplating suing him in small claims court. It's a little fuzzy whether I can sue him out-of-state since he runs an Internet-based business or whether I have to file in PA. The latter is more complicated logistically, and it's unlikely I'll ever see any money.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #17 on: May 28, 2011, 11:55:11 am »
I swapped out the chassis. The good news is that everything works, but the bad news is that the picture problems are identical. Now, it's possible that both chassis are similar in age and have identical problems with the capacitors, but it's a little too identical for that. In addition to the right-to-left wave/ ripple, I still have the problem that the picture is too tall as well. Of course, it's entirely possible I fried both chassis in an identical manner by not powering it via an isolation transformer.

There are a few more knobs on the chassis I haven't tried: (VR105) PIH-CUSH, (C392) V.LINE and (VR104) B+ADJ. I have no idea what the first two do, and I understand that the B+ is to regulate the DC voltage. Before I start messing anything up, is there reason to believe these controls can help correct my picture problems?

Thanks!

lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #18 on: May 28, 2011, 12:46:21 pm »
The first is a pincushion adjustment. It will control the left and right sides to make them bow out like a baloon or curve in.

The second is what's often called vertical linearity. It ensures the beam scan throughout the image is constant and doesn't speed up or slow down. If you display squares on the monitor the squares will all be identical. If the v.line is off, the ones near the middle of the screen would be rectagular instead of square. Adjusting it will squish them back to square.

Don't mess with the B+... Nuff said :P

BobA

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Re: Blowing fuses - replace or repair?
« Reply #19 on: May 28, 2011, 01:23:23 pm »
Have you got a picture of your CRT showing the problems.   Also just wanted to check that the tube is mounted vertically as the 60 in 1 needs a vertical display.   What the heck no iso trans maybe the tube is mounted horiz.

Kevin Mullins

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Re: Blowing fuses - replace or repair?
« Reply #20 on: May 28, 2011, 02:38:43 pm »
Don't mess with the B+... Nuff said :P

A low B+ "could" cause waves and ripples.... BUT .... without knowing exactly what it should measure and where to measure it from I wouldn't touch it just yet.

The Vertical Linearity "might" help with the vertical size a bit.

I noticed that there is nothing earth grounded except for the switching power supply.
You could try running a ground wire up to the metal frame surrounding the tube.
That black wire should lead to a metal "braided" looking wire going around/across the backside of the tube. You can connect the ground to anything that that is connected to.
Not a technician . . . . just a DIY'er.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #21 on: May 29, 2011, 11:17:59 am »
The first is a pincushion adjustment. It will control the left and right sides to make them bow out like a baloon or curve in.

The second is what's often called vertical linearity. It ensures the beam scan throughout the image is constant and doesn't speed up or slow down. If you display squares on the monitor the squares will all be identical. If the v.line is off, the ones near the middle of the screen would be rectagular instead of square. Adjusting it will squish them back to square.

Don't mess with the B+... Nuff said :P
Thanks lilshawn, that helps. Yeah, I'm not too eager to mess with the B+ adjustment, seems like a good way to ruin the chassis. This is probably going to be the measure of last resort.

Have you got a picture of your CRT showing the problems.   Also just wanted to check that the tube is mounted vertically as the 60 in 1 needs a vertical display.   What the heck no iso trans maybe the tube is mounted horiz.
Here are a couple of pictures.





I also uploaded a couple of short videos to Youtube. As for mounting orientation, yes it's mounted vertically. But that's a good question to ask, given the history with this joker NOTHING should be taken for granted  :banghead:



A low B+ "could" cause waves and ripples.... BUT .... without knowing exactly what it should measure and where to measure it from I wouldn't touch it just yet.

The Vertical Linearity "might" help with the vertical size a bit.

I noticed that there is nothing earth grounded except for the switching power supply.
You could try running a ground wire up to the metal frame surrounding the tube.
That black wire should lead to a metal "braided" looking wire going around/across the backside of the tube. You can connect the ground to anything that that is connected to.
Good suggestion. I added a ground wire to the monitor. I connected one end to the ground wire in the power cord and wrapped the other end around the braided wire. It didn't solve the wavy picture, but it was still a good thing to do.

The rippling is worst at the top and the bottom. It's visible in the middle, but when you're playing a game like Galaga, it's actually not too bad.

windmill

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Re: Blowing fuses - replace or repair?
« Reply #22 on: May 29, 2011, 11:59:59 am »
What the heck no iso trans maybe the tube is mounted horiz.
Just to add to that...the machine has two setup buttons ("Test" and "Service"). Test works, but he wired Service into Coin2. I mean, how can you miss that. Also, it appears this machine doesn't save any settings or high scores when powered off. More annoyances. I know, these aren't monitor problems, just venting here.

lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #23 on: May 29, 2011, 01:08:28 pm »
Just to add to that...the machine has two setup buttons ("Test" and "Service"). Test works, but he wired Service into Coin2. I mean, how can you miss that.

nothing with this cab is surprising me now

Also, it appears this machine doesn't save any settings or high scores when powered off. More annoyances. I know, these aren't monitor problems, just venting here.

we have a few of these boards, unfortunately they don't save high scores.


as for your monitor, it's has 2 problems... you have a slight pincushion problem. tweaking that vr105 pot will fix it. but it's also doing the "hula" it might just be the b+... do you have a multimeter to test what the b+ is? maybe the power regulator is messed up due to the no iso issue. hard to tell.

if you can get a B+ reading that would be great.

P.S. the voltage is going to be in the 200 volts DC range... be sure to take proper precautions regarding HIGH VOLTAGE

windmill

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Re: Blowing fuses - replace or repair?
« Reply #24 on: May 29, 2011, 02:04:49 pm »
as for your monitor, it's has 2 problems... you have a slight pincushion problem. tweaking that vr105 pot will fix it. but it's also doing the "hula" it might just be the b+... do you have a multimeter to test what the b+ is? maybe the power regulator is messed up due to the no iso issue. hard to tell.

if you can get a B+ reading that would be great.

P.S. the voltage is going to be in the 200 volts DC range... be sure to take proper precautions regarding HIGH VOLTAGE
Yes, I have a multimeter. I looked for some info on how to measure the B+ voltage, is this done by simply putting the probes on either side of the potentiometer? The B+ pot is in a pretty awkward spot, so I'll need to take it off the side of the cab and flip it upside down. Good thing all the wires have a little slack. And I appreciate the warning about high voltage. I'm fairly comfortable about electricity, but not so comfortable I don't have a healthy respect for anything over 12V....

But yes, there is definitely a good chance I messed up the board when I plugged it in without an iso. But the good news is that the tube is working. If I need to shell out another $75 for a replacement chassis (the unfried variety), I'm still coming out ahead vs. buying a replacement LCD monitor. And I've learned a couple of things along the way.


lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #25 on: May 29, 2011, 02:15:12 pm »
Quote
Yes, I have a multimeter. I looked for some info on how to measure the B+ voltage, is this done by simply putting the probes on either side of the potentiometer?

i don't think so... your going to have to find where your regulator is and measure the voltage coming out of it. the pot only provides feedback to the regulator to adjust the voltage coming out.

EDIT: ive been searching around for a schematic for this chassis and haven't found anything yet. without a schematic of some sorts, i wouldn't attempt any repairs just yet.

EDIT2: another intersting tidbit of info that might come in handy for you: http://forum.arcadecontrols.com/index.php?topic=42849.0
« Last Edit: May 29, 2011, 02:28:44 pm by lilshawn »

windmill

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Re: Blowing fuses - replace or repair?
« Reply #26 on: May 30, 2011, 01:09:02 am »
EDIT: ive been searching around for a schematic for this chassis and haven't found anything yet. without a schematic of some sorts, i wouldn't attempt any repairs just yet.

EDIT2: another intersting tidbit of info that might come in handy for you: http://forum.arcadecontrols.com/index.php?topic=42849.0
Yeah, without the right info this would be complicated. I mean, I could blindly turn up the B+ and see what happens, but I'm not terribly comfortable with that. Any chance I can damage the tube this way, or would the damage be limited to just the board?

And thanks for the link to the other thread that has the link to Alva! The prices listed are from 2005, but assuming they haven't changed too drastically, I think I'll go ahead and order one.

Sanity check question - or more like putting my newfound paranoia to rest. The fact that the tube works with this chassis (albeit with a wavy picture), does this mean the chassis is actually compatible? You'd think that the person who built this cab would select compatible parts, but as discussed before, I'm not trusting anything at this point. I googled the part number for the tube (it's an RCA), but came up empty.

lilshawn

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Re: Blowing fuses - replace or repair?
« Reply #27 on: May 30, 2011, 09:29:17 am »
Quote
Sanity check question - or more like putting my newfound paranoia to rest. The fact that the tube works with this chassis (albeit with a wavy picture), does this mean the chassis is actually compatible? You'd think that the person who built this cab would select compatible parts, but as discussed before, I'm not trusting anything at this point. I googled the part number for the tube (it's an RCA), but came up empty.

it's a crap shoot. This chassis you have is a universal one to begin with... perhaps it's right on the edge of compatibility with this yoke/tube setup. it's hard to tell without having a proper test done on it.

i can say for certain that the tube and yoke are good, since you do get a picture, and the colors are all good and bright.

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Re: Blowing fuses - replace or repair?
« Reply #28 on: June 01, 2011, 11:43:25 am »
it's a crap shoot. This chassis you have is a universal one to begin with... perhaps it's right on the edge of compatibility with this yoke/tube setup. it's hard to tell without having a proper test done on it.

i can say for certain that the tube and yoke are good, since you do get a picture, and the colors are all good and bright.
I ordered a new chassis today from Alva Amusement. Worst case, someone is going to get a bargain on an almost-new chassis next week, and I'll come back to bug everyone for alternatives :lol
Keeping my fingers crossed...

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Re: Blowing fuses - replace or repair?
« Reply #29 on: June 01, 2011, 06:34:23 pm »
EDIT: ive been searching around for a schematic for this chassis and haven't found anything yet. without a schematic of some sorts, i wouldn't attempt any repairs just yet.

http://home.comcast.net/~mtpacifico/_kenskorner/files/Wei-ya%20825HR%20Schematic.pdf

I personally would be tempted to bump the B+ up a tad and see what happens.  ;D
Not a technician . . . . just a DIY'er.

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Re: Blowing fuses - replace or repair?
« Reply #30 on: June 01, 2011, 10:49:06 pm »
EDIT: ive been searching around for a schematic for this chassis and haven't found anything yet. without a schematic of some sorts, i wouldn't attempt any repairs just yet.

http://home.comcast.net/~mtpacifico/_kenskorner/files/Wei-ya%20825HR%20Schematic.pdf

I personally would be tempted to bump the B+ up a tad and see what happens.  ;D
I might still do that, just to see what happens. But I think my wife is getting tired of the machine being open every day with a bunch of tools spread out across the floor. So with a new chassis in hand, I can blow up the old chassis and replace it with the new one all in a single session :D If by sheer luck bumping up the voltage solves the problem (and I manage not to electrocute myself in the process), well, that's still good news! And if it doesn't, I'll be enriched by the experience of frying my first chassis, gaining me much street cred.

I don't think I can damage the tube this way, so at this point I don't have anything to lose  >:D

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Re: Blowing fuses - replace or repair?
« Reply #31 on: June 01, 2011, 11:05:43 pm »
Wow...the things people do to avoid using a "proper" power supply on low cost monitors...  I'm also continually amazed at how well people can draw schematics that electrically define a circuit without conveying any intention behind it at all...

I'm also amused by the obvious additions to the schematic image outside of whatever program was originally used to draw it.

If I had to guess, B+ is supposed to be 120-130V, which is typical.  I wouldn't go much above 140V if you are inclined to turn it up.  Stuff will definitely start having their ratings exceeded around 150-160V.  I'd measure all the secondary voltages where marked and see what you get, as well.  B+ can be measured at the + side of C220, which should be a big boy near the AC input.  Note: it'll be measured relative to the frame, which should be connected to ground, not the - side of the cap.

You've very unlikely to damage the tube itself, so if you aren't concerned about blowing up stuff on your chassis, have at :)

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Re: Blowing fuses - replace or repair?
« Reply #32 on: June 05, 2011, 04:00:16 pm »
I ordered a new chassis today from Alva Amusement. Worst case, someone is going to get a bargain on an almost-new chassis next week, and I'll come back to bug everyone for alternatives :lol
Keeping my fingers crossed...

The new chassis got here last Friday, gotta love two day shipping. Before installing it, I played around with the B+ voltage on the old board, but that didn't seem to do anything to the picture.
So out with the old, in with the new. The good news is that the picture is no longer wavy, it's steady as can be.  :D The bad news is that there are raster lines that appear on the right hand side of the picture  :cry:
I've played with all the settings, and nothing seems to help. The lines get more pronounced if I increase the Screen setting. It only affects the right 1/3 of the screen.





Did I just get unlucky with a bad board?

Also, as you can see from the rounding at the bottom and top there is a noticeable pincushion effect. I adjusted it as far as it will go, and it's not bad, but it's definitely not close to "good enough". On the other hand, the vertical size problem (although technically it would be the horizontal size problem since the monitor is in the vertical position) seems to have been solved, everything fits on the screen with this new board.

I must admit, I'm rather disappointed that I've swapped one problem for another...

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Re: Blowing fuses - replace or repair?
« Reply #33 on: June 05, 2011, 05:14:33 pm »
could be a crt/chassis mismatch-you would need to read the yoke and post the readings here

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Re: Blowing fuses - replace or repair?
« Reply #34 on: June 05, 2011, 07:11:13 pm »
You need to measure the 5DCV going to the game board.  Make sure this is 5V.  Also, have you tried lowering the brightness?  Cold solder joints will cause this as well.  Good luck!

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Re: Blowing fuses - replace or repair?
« Reply #35 on: June 05, 2011, 11:07:04 pm »
could be a crt/chassis mismatch-you would need to read the yoke and post the readings here
Grantspain - I'm not sure what you're asking me to measure.

You need to measure the 5DCV going to the game board.  Make sure this is 5V.  Also, have you tried lowering the brightness?  Cold solder joints will cause this as well.  Good luck!
I checked the voltages on the PSU. The +5V reads +5.16V, the +12V reads +12.12V and the -5V reads -4.81V. I tried lowering the brightness, but this didn't help any. When you say cold solder joints, are you talking about a joint on the chassis, the isolation transformer, the game board, or the power block? Or all of them?

But your question on the game board got me thinking on whether I may have damaged the PSU or the iCade board accidentally. Before installing the new chassis I discharged the CRT, but I did not disconnect the ground wire first (which connects to the PSU). Since the machine was not plugged in when I discharged it, it was essentially ungrounded. I know, not smart... Unfortunately, I don't have any parts to verify this. I could order a new PSU and board of course...

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Re: Blowing fuses - replace or repair?
« Reply #36 on: June 06, 2011, 04:37:46 pm »
Does adjusting the Vertical Height help ?
(shrink it)

Not a technician . . . . just a DIY'er.

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Re: Blowing fuses - replace or repair?
« Reply #37 on: June 06, 2011, 06:00:17 pm »
Does adjusting the Vertical Height help ?
(shrink it)

It doesn't make a difference. If I shrink the screen (centering the picture), the lines remain, they just move to the left (and get narrower along with everything else).

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Re: Blowing fuses - replace or repair?
« Reply #38 on: June 20, 2011, 06:41:24 pm »
The saga continues!

I contacted Raul at Alva about the problem. He suspected a bad capacitor in the horizontal circuit and told me to ship it back for a replacement. He checked the board and didn't find anything wrong with it though. After going through the entire history, he suggested I look at replacing the voltage regulator transistor on the original chassis, as it was likely it was damaged when I plugged it in without the iso. Even though he thought the chassis he sent me was fine, he still offered to send a replacement chassis. Or refund my money, my choice. His words: I prefer to offer solutions, not make money off people's problems.  :notworthy: Hard to beat that kind of customer service.

Anyway, I think I'll try replacing the transistor first. Bob Roberts has it in stock, and I owe him a few dollars anyway because he undercharged me for shipping the iso. Of course, this means I will have to solder something other than a power connection for the first time ever, so that will be excitement all by itself.

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Re: Blowing fuses - replace or repair?
« Reply #39 on: June 26, 2011, 08:38:19 pm »
Excellent progress today! Bob Roberts cross-shipped the voltage regulator transistor and it got here in time for the weekend fun. I admit, I was a little nervous desoldering my first component, but everything went well. After removing the old transistor, I soldered up the new part. Luckily I still had some thermal transfer compound left over (1 tube lasts a lifetime...just like chapstick...), so the whole deal took less than 15 minutes. The picture is now super stable! No more waviness or ripples!  :cheers: :cheers: :cheers: Kudos to Raul from Alva for diagnosing this.

I still need to do a little tweaking here and there, but this is a vast improvement. The only problem I still have is that the picture is still too tall (which given the monitor orientation means it's really too wide). I've maxed out the horizontal width, which means I can either play Galaga with either the spaceship or the score visible. I want both! I know, picky picky :lol