I don't believe it, another classic added => Centipede ! FINISHED !!!!

[Level42]

Hey Fredster thanks for that info !

I don't guess I can still get those oldy RAMs around here... I think I'm going to have to do a pretty big order with Bob Roberts (Big Blue, trackball parts etc.), the only problem is it's very hard to order from Bob from outside the US. He doesn't accept PayPal or CC, which both are my options for international orders.

Do you think the 6502C from an Atari 800XL will work (just to check)....I got one here. I read the C has one extra pin that should be kept high to enable it. Think that's the only real difference.

Well the easiest thing would be buying your board of course, but something is telling me I ought to try and repair this one. Not for the money really, but, you know, a saved board is another saved board....
I'm pretty good in electronics, but it's not my daytime job to hunt down digital PCBs, but I do want to give it a try. I will definitly need that oscilloscope (wish I had an Atari CAT box )

Your knowledge and experience could really help me out Fredster ! Until march 28th, I'm really very tied up with other things in my spare time, so it'll take a little while before I start on the Centipede. I also want to finish the Galaxian ASAP. Thanks about the cones Fredster, but I already got some from Luigi, see his kind offer But thanks anyway...

I love this forum !!! 

[Level42]

So far, I've only checked the voltages on the PCB test points and they seem to be fine. What I did do, was change the plug on the power supply. My power supply is the European version. By changing the plugs, you select the voltage it operates on. It was on 220VAC when I got it. However, in recent years, the mains voltage has been increased to 230VAC on mainland Europe. (UK lowered it from 240VAC to also 230VAC). This to reach one standard voltage within Europe. The result was that some voltages were a bit on the high side (not the regulated one's of course, f.i. the 5V was 5.01 Volts).

So I switched it to the 240V connector and that lowered things a bit.

Still the same thing on screen.....just random characters from the game like centipede parts, spider, mushrooms, shooter etc. and they are standing still. The reset button has no effect (I checked it, the button itself works fine). I removed all socketed chips, and re-inserted them. There have been IC's replaced on the board, I can see that from soldering marks. Solderings look ok generaly. Could there also be problems with the sockets (corrosion ?) the pins on the socketed IC's looked very clean though..

[Level42]

OK I did some research about the RAM on the Centipede PCB's. I made a small Excel file that's attached here.

There's something strange about the RAM chip on C8 position. It's mentioned as 82525 or B2525 on the manual but there's a 6560N on my PCB.

I also found another source for those chips: www.arcadechips.com has everything but the 6560N. They have an on-line ordering system, ship international AND accept PayPal.
Price's are right too. They also have 6502 and even Atari's Big Blue.

The Service Manual mentions that the board "shows" any RAM errors with beepcodes (was Atari ahead of it's time or not ? ) There's a range from 1 to 10 each indicating for a certain RAM that MAY be bad.
"Any bad RAM  must be replaced before the computer can check the other RAMs, as well as continue with the self-test." (Service Manual quote)

Now I don't hear any beeps. In fact, I only hear a scratching sound when powering up the cab when it's been off for a while. If I turn it off and switch it back on again after 10 seconds there's no sound at all...(elco's ?)
I could monitor the sound on the test-points to see if there's any beeps to be heared.

But I think I will order a full set of RAMs anyway...they're cheap enough...

I don't have a logic probe, but I do have an Oszifox. This is a pen-shaped measuring device, that's actualy a tiny osciloscope.
http://www.wittig-technologies.com/english/05_products/01_oszifox/oszifox_01_intro.htm

The bandwidth is only 5 Mhz, but that should be enough for a board running on 2 Mhz. You can connect this to a PC (regretfully not Mac) via RS-232 and run scope software. I didn't do that (yet), there's also a small display on it that shows the waveform etc.

So I poked around with it on the board. Sure enough there's a clock signal and I've checked many pins on RAMs, 6502 and Pokey. All show lines going high/low. So there's definitely life in it

I also hooked up my DVM in diode-test (yes I did power down the PCB first ) and measured to ground all pins of RAMs that are on the board in 2 or more to compare. All the 2101/9101's showed identical values. However, on the 2114's I got different results on some pins...

Pin 13 and 14 show different values between H2 and F2. Could this indicate a bad ram ? The lines on those pins go straight to E2 that is a 74LS245, a bus transmitter/receiver. Here I measure the same "wrong" values on pin 6 and 7 (which is logical of course). So, the 74LS245 could also be bad...any suggestions before I desolder the pins to check this out ?

[RayB]

Wow, so much work, $$ and shipping, with no guarantees, when you could just buy a working board.

[Level42]

Well, a working PCB would cost me almost $100,- incl. shipping.

The RAM's will be a lot less. I THINK I am on the right track, if so, I would only need a single 2114....at $1,60 (anyone has a spare ?).
In all honesty www.arcadechips.com has a minimum order of $15,- but I will probably throw in a Big Blue anyway and that's $11,- already. Include an extra 2114 and an extra 2101 or two and I'm at the $15,-. Shipping is only $5,- USPS ground (I'm in no rush). So that's about $20,-

Also, there's 2 more reasons to do this:
1) The challenge
2) The fact of saving a Centipede PCB

I know that both will give me a kick IF I get the board back to life
Throwing away a PCB that has only 1 bad chip would make me feel bad

Indeed, there's no guarantees, but I like to learn ! Maybe I will regret it later, but at least I've tried then...

[Edit] Think about this: I could have bought a completely restored and working Centipede cab for, let's say $1800.- and have it shipped here for another....let's say $400,-

Besides not having the money for that, there's no glory in it.... restoring the game is at least as much fun as playing it...

[sfrascella]

Besides not having the money for that, there's no glory in it.... restoring the game is at least as much fun as playing it...

I couldn't agree more. I have a Defender and a Galaxian that I'm working on right now, and would probably break even on the Defender if I were to sell it but the experience and the fun I have had far outweigh the cost to me.

[fredster]

Wow, so much work, $$ and shipping, with no guarantees, when you could just buy a working board.

RayB, He wants to learn how to fix these things.  I fixed a few of them, and it's really rewarding.

Level42, you are on the right track, but it's not brain surgery.  I doubt if it is very much that's wrong with it.  Those Ram Chips are the most common failure.  Replace those chips with seats and plug them in. 

It could be a +5V problem if it isn't the ram chips.  The 12V is for the audio. You won't know if it's working until you can coin it up. It should have beeped.  But put it into test mode after you replace the chips.  Try it AFTER every chip!

I hope you found some more repair logs - Mike's arcade knows a lot about this: http://www.mikesarcade.com/arcade/repairs/centipede.html

You did ask the "elders" on the RGVAC?

One other tip:  Those old boards get really sensitive to soldering.  The chips are rotted to the board sometimes and you can pull up the traces when you take out the chip.  UGH I hate that.  Make sure you get rid of all the solder before you start tugging at it.  Check the continuity of the traces after you put the seats in to make sure they connect where they are supposed to.

That looks like a Ram error to me.  Check the history on the RGVAC.

[Level42]

Yep Sfracella and Fredster are right.  I doubt the 5V is a problem, it's VERY good still after all this time (5.01 Volts on my Fluke DMM). There's also almost no ripple on the DC supply voltages, so I actualy wonder if the Big Blue needs replacement....well It coulnd' hurt I guess for just 11 bucks...

Yes I found the repair guides on Mikes Arcade, but none of the Centipede one's are about my problem as far as I read.

Indeed the RAM chips seem to be fragile, there are already three on my PCB replaced before.

I aksed some questions to arcadechips and will then order a nice set of RAMs...

Thanks for all the help Fredster !

[Level42]

Incidently found a lot of Centipede Repair info here:

http://www.2coinsperplay.com/Tech/Video/repairs/repair%20Logs/Centipede/Centipede%20Repair%20Log.html

And there's also a good general write-up of Videogame PCB repair:
http://www.2coinsperplay.com/Tech/Video/Hints%20on%20repairing%20arcade%20boards.html

If you read the section about bad RAM, you can see this is exactly "my" problem...great...

[RayB]

Level, is it safe to assume at this point, that you've given the board a proper scrutinizing, looking for broken traces, broken capacitor legs or missing caps? Bad/Broken caps feeding power to the RAMs will also result in RAM errors.

[Level42]

Level, is it safe to assume at this point, that you've given the board a proper scrutinizing, looking for broken traces, broken capacitor legs or missing caps? Bad/Broken caps feeding power to the RAMs will also result in RAM errors.

Mmmm, well I did a lot of looking at the board, but didn't specificaly look for that. However, since the two lines that run directly from one of the two 2114's to the bus driver (74LS245) mearure very differently to GND then all the others I think that one of those 2114 is the cause for the problem.

The 2114's are first in the memory map of the Centipede PCB, and the service manual (and self-test beeps) check these two rams first. This added to the info Fredster gave and the info  I found on 2coinsperplay.com leads me to being pretty sure about this....

However, there is a good chance that there may be more problems of course. By looking at the sodlerings you can easily identify if any chips have been replaced already. Three chips of the "main" (Playfield) RAM had already been replaced. However these all measure the same on the same leads per chip. So I expect them to be OK.

There were two or three other chips replaced as well, and the soldering job looked not too good, so I tried re-flowing it. I instantly learned from that that soldering an old PCB like this is a risky and delicate job. The old flux seemed to be baking away !

Anyway, it's definitly worth visiualy checking again the PCB and the parts for any other problems for sure.

I'd love to have a CAT-box ! It shouldn't be too hard to "emulate" one with a PC and some hardware should it ?

[RayB]

I'd love to have a CAT-box ! It shouldn't be too hard to "emulate" one with a PC and some hardware should it ?

That's a good question. They are rare and fetch a high price on Ebay. I have not ever heard of anyone trying to build their own.

[Level42]

I'd love to have a CAT-box ! It shouldn't be too hard to "emulate" one with a PC and some hardware should it ?

That's a good question. They are rare and fetch a high price on Ebay. I have not ever heard of anyone trying to build their own.

Yeah, but I think the high price is based mostly on the collecting value. I have seen someone who had some plans about it, but it seemed to have never materialised.

I must be missing a lot, but as far as I understand, basicaly you put adresses on the adress bus and write data to it that then gets read back and compared. You can also put in a range and the have it pulse through all the adresses in that range and compare....looks pretty simple to me,but although I'm an electronics service man, I'm not an electronics designer

It would be a powerful tool and a fun project.

[Level42]

I ordered a set of all sort of RAMs that are on the Centipede PCB plus the buffer IC and the High-Score memory from www.arcadechips.com
Ordered yesterday, shipped today 

The IC I could not identify turns out to be a 82S25 and not a 82525....this is also available at www.arcadechips.com

Hope it will solve the problem !

[fredster]

Level42,

I screwed up more than one trace by soldering an old area.  You have to check continuity of each of the traces around the chips.  Somebody may have screwed up the repair and gave up on it.

Check each one and then make sure it's good.  They are pretty big traces.  Use the multimeter to track them down from edge to edge and see if they are okay.

It's easy to fix if you find one dead, get that really small wire at an electronics store that's made for this.  All you have to do is touch it to the trace and you have a new one.

Go ahead and look at the board.  Really really look at it with a magnifying glass and a bright light.  Look at each repaired area and see if you see anything that is burnt or lifted.  That could be a problem.

Most of the time, you can see what's wrong.  You may have a dead trace. One that was okay for a while, then went bad later in use.

[Level42]

Well the RAM that I suspect is defective is still the original. It has the original solderings that is not tampered with and looks fine. I've closely examined it and did conductivity tests.

The chip I mentioned was near the PCB connectors. I tested that also after re-flowing the solder and the connections were fine still.

I'm now waiting for the RAMs and other chips to arrive from www.arcadechips.com

The have good prices compared to what you see on e-bay !

[Numbski]

Dude...you gotta let me trade notes with you!

I just had a cab laid on me that was supposed to be Capcom's "Avengers".  I finally deducted from the screen burn-in that it's Centipede, and after seeing your images, there's no question that is what I have on my hands!

My camera is at the office, but at my next opportunity I'll take pictures...but be warned, they will disgust you.

There's droppings inside the cab, coin mechs are hosed, monitor is burned in...they tried to use some sort of clear epoxy to fill in the old trackball hole, and painted over the original art with some weird gray primer.  Scraping away the gray I can kinda-sort see the old art.  You think your restore is going to be tricky?

Pfft.

[Numbski]

Huh.  Went and scraped some of hte paint off last night, and my side art has the pink outline instead of yellow as well.

This is getting weird.   I need to get my camera from my office and take some pictures before I do too much more to this.

[Level42]

Yeahhh, we want pics !

I never said that my Centipede needed a tricky restore (that's also why I paid a reasonable amount for it). To list it up:

1) Monitor repair or replacement. I think I may try a repair again, just for the originality and the burn-in is not too bad. I like that grey looking CRT
Plus a G07 should be pretty easy to repair with a repair-kit from Bob Roberts.

2) PCB repair. Could be hard,could be easy. I think I already found one problem. IC's are on their way across the Atlantic...

3) New CPO.....a no-brainer

4) Start buttons and cones, ordered from Luigi in Germany, should be on their way....

5) Controls.....I think I will get that Ice-button thing from GGG. And also a nice Ice Trackball. And then light it all up in red. Looks pretty original when off, and funky when on.....

6) New Coindoor. Mine is not that bad but there IS a dent in it and I got one offered here in The Netherlands for a trade. Will probably pick it up the end of the week.

7) Very likely I will treat it with some new T-molding.

8 ) Trackball. This could either be some good cleaning or new barings and rollers...probably the last one while I have to order the monitor repair kit from Bob Roberts anyway...

9) Install and re-wire a coin mech.

10) Lotsa cleaning


Mmmm, still pretty much when listed up like that

I'm waiting with ordering the parts listed because I want to finish the Galaxian first and I might....might....might be getting another cab......gulb.....yes I mean it. And I have no CLUE where to store it until my Game Room is materialised.......but if I will get it, I will have a pretty unique collection for the low countries IMHO

I'm not sure but I think here in Europe cabs were not so much converted as in the US. The cabs I've seen on offer so far here are almost all in their original state, or they are generic (Royal Video/Playscene) cabs.

My Galaxian was previously owned by a dentist who had it in his waiting room. Now that's a dentist I would like to go to, but what if you're working on your high score and it's your turn for "the chair" The cab has been in commercial use though, since there's a license plate from 1989 on it....I always like to know something of the history of the cab....

Too long posting I know....but I haven't had time to do anything on my projects lately so this is probably some compensation

[Level42]

Hey Centipede lovers, check out this one:
eBay Link

Look at that CPO ! Is that a Willis clone or something ? Doesn't really show well on this pic, but it looks kinda cool !

[Edit] Oops: http://forum.arcadecontrols.com/index.php?topic=21614.0
So yes it's a Willis. I wonder if it's in that big bag of Arcade Art from classicarcadegraffix.......

Not that I will use it.....gotta keep it original. I kinda like the Centipede figure, but it's too clear it's not like the original art....

[Numbski]

Hmm.  The art and CPO on mine is completely shot.  I'm going to make every effort to stay original on mine, but I'm not going to go too nuts on it.  If something is "close enough", then  I mia just run with it.  It's not going to be original, no point in trying to force it.  As a result, I may go with the ICET trackball, so long as it works, and perhaps a lit fire button.

I'll try to remember to bring my camera home today.  Here's my shopping list:

Trackball
Centipede Mainboard
Marquee
Power Supply (pretty sure it's not the original, but not certain.)
Side Art
Kilz (for the insides...it *STINKS*!)

[Numbski]

I never made it to my office yesterday.  I have to today (in fact, I'm headed there now), so pictures this evening.

Question - the side art on this thing is shot, without question.  I'm thinking that I should go ahead and use citristip, sand, bondo any damage, prime, sand, prime, sand, perhaps a coat of white, sand.   The side art is a full cover, right?  Or should I get a good base of white, presuming that the repro-art is just the graphics that I need to center on the sides? 

[Level42]

IMHO it should be a full cover, just like the original. Check out http://www.retrospieler.de/
Allthough this is a repro cab, he did use the fuil side-art. Gotta cut it into shape yourself.

[Level42]

O yeah, and www.arcadeshop.com (where the above mentioned side-art was coming from) has plenty other nice Centipede parts as well.

[Luigi]

Well, a working PCB would cost me almost $100,- incl. shipping.

I bought my Robotron PCB set for $200 from a total stranger: John Overchuk (www.barncade.com). Just posted in the google groiups - he mailed me that he has one working set for sale - money transferred - pcbs received - Robotron runs again   That's just the way it should be !!  Thanks again from this point John 


Back to business.

Man, you are doing a great job here......keep going.


Money is here, all I need is your address. I searched the mails and posts but I couldn't find it

[Level42]

I bought my Robotron PCB set for $200 from a total stranger: John Overchuk (www.barncade.com). Just posted in the google groiups - he mailed me that he has one working set for sale - money transferred - pcbs received - Robotron runs again   That's just the way it should be !!  Thanks again from this point John 

[/quote] Well I think an original Centipede PCB deserves a fair chance on a repair. And I've used up pretty much of my budget by buying three very nice classic cabs in a very short time AND ordering all sorts of stuff for them. (That's why I was so glad with your offer for the buttons and cones for a very good price !)

But the main reason is that I think I have the capabilities to repair it and hope to succeed.

If playing the game is the only/main goal and/or you don't have the skill/tools to repair, then yes order PCB's and revive that cab !

Man, you are doing a great job here......keep going.

Thanks, I will. I just received the IC's from www.arcadechips.com !! Pretty fast and well packed in the "chip carriers". The chips are brand new as far as I can see.

I hope to do some work on the PCB this weekend.

Money is here, all I need is your address. I searched the mails and posts but I couldn't find it

PM sent !

[Numbski]

In my case, there was no PCB.  Have to hunt one down.  Have camera, pics to follow....

[Luigi]

Oh, I didn't want to say that you should stop trying to repair the PCB...of course NOT !!

If it isn't broken in four or more pieces there is a very good chance that it can be repaired (I once saw an Asteroids PCB where the tracks had already started to vanish.....don't know....some kind of acid or such stuff.


Please PM me with your address !!!  I've tested the switches with 3V and they both worked

[Numbski]

Pictures ahoy....presuming Flickr is nicer to you than it is to me.  When I'm logged in, they show.  When I'm not, tosses an error about not being able to find my profile or my pictures...hoping it's just a database propogation thing though.

http://www.flickr.com/photos/7545690@N03/sets/72157600033257355/

Just in case I linked to it wrong somehow:

http://www.flickr.com/search/people/?q=Numbski&m=names

[Numbski]

Looks like the database replication caught up, and the links work now.

The ones of interest (or sadness, if you will):

Full right side shot:

http://www.flickr.com/photos/7545690@N03/437848162/in/set-72157600033257355/

Orange goo under the control panel:

http://www.flickr.com/photos/7545690@N03/437848154/in/set-72157600033257355/

and of course, slidehow!

http://www.flickr.com/photos/7545690@N03/sets/72157600033257355/show/

[Level42]

Wow, my Centipede surely has been treated a LOT better than yours ! But you paid WAAAYYYY less than I did, but you're gonna need it for LOTS of things.....

F.i. that power supply is not going to do anything for a Centipede PCB. You will need all the "weird" voltages from a real Atari PSU....Maybe it would be cheaper to see if you can find one of those newer Centipede/Missile Command/Bowling game combo PCB's, but I guess these are quite rare.

[Level42]

I will be trying the repair on the PCB soon. Can anybody tell me if I can run the PCB on 5V (and maybe also 12V) only ? Just to check if things are running ?

My cab is temporarely stored in my shed so I would like to be able to do some testing outside of the cab...
Maybe Fredster knows this ?

[Level42]

Well I started my repair attempts today by replacing the 2114 that I suspected to be defective.

My method of replacing IC's:
1) re-tin all the pins of the IC on the solder side with new soldering tin. This will make it flow much better later.
2) cut off the pins of the old IC with a really tiny and sharp cutting pliers, as close as possible to the top of the pins.
3) remove the body of the IC when all pins are cut
4) position the PCB on it's side using something to let it lean on. Now hold the cut-off end of a pin  with small pliers and use the soldering iron on the other side. Now it's easy te remove the pin. Repeat on all pins of course..
5) Move the PCB back on it's components (solder side up). Remove all solder from the soldering holes using a tin-sucker and my regular soldering iron.
6) Clean the area and check for any "left-over" tin particles on the PCB.
7) Check all the leads going from the IC holes to the connected side with a DVM in diode test.
Insert a GOOD quality IC socket
9) Solder all the pins...duh.....ready !

I measured the pins again that showed different results between the two 2114's beforee and this time the values are exactly correct between the two ! So i have high hopes.....

The really sad thing is that my cab is deep down in my shed at this moment....so I can't test it yet AAARRGHHH !!! Could it run on just +5V and +12 V Just to test  ??

[Level42]

More pics......those damn sockets almost cost me more than the IC's !!!! Arcadechips.com should start selling these as well

[Numbski]

Okay....took a few more pictures today.  Got the control panel off and started the process of stripping it down to bare metal.  I could use some help identifying holes.   I think the two "filled" holes to the left are the "cone" style buttons that I need to hunt down.  Anyone feel like helping me point out which holes need filled, and which ones need opened up?

Also, I guess I need some help in hunting down said cone buttons.

My plan right now is to fill in all unneeded holes with bondo, sand the whole thing super-smooth, prime, and a decent coat or two of black paint.  Done right, shouldn't be able to tell it was ever converted.

Here's a link to the pics from just today:

http://www.flickr.com/photos/numbski/archives/date-posted/2007/04/01/

[Level42]

Okay....took a few more pictures today.  Got the control panel off and started the process of stripping it down to bare metal.  I could use some help identifying holes.   I think the two "filled" holes to the left are the "cone" style buttons that I need to hunt down.  Anyone feel like helping me point out which holes need filled, and which ones need opened up?

I think you already found the trackball and player 1 & 2 holes. Looks to me that the top hole (with the small cut-in) is the only real one.....there's plenty of pics in this thread for reference.....

Also, I guess I need some help in hunting down said cone buttons.

Luigi already offered them and either used or new pushbuttons in this very thread for very reasonable prices

[Numbski]

Couple of silly questions then - since I never was much of a fan of Centipede (I think mostly because every trackball I came across sucked, and I always got my hands pinched on the side!)

1.  Are there supposed to be any carriage bolts or plexi?  It looks like maybe there are 4 visible that hold the trackball into place, but no plexi.

2.  Should I go with a leaf-switch button?  I'm almost tempted to go with a Sanwa pushbutton, both because of soft feel and more reliable.  Dunno there...

Those trackballs at groovygamegear.com don't look like they'll work here, so I guess it's a standard white trackball for me.   

[RayB]

1.  Are there supposed to be any carriage bolts or plexi?  It looks like maybe there are 4 visible that hold the trackball into place, but no plexi.

ARRRGGH!!! Of course no plexi! THat's a modern-day thing, mostly started by operators adding it to control panels. NO PLEXI!

2.  Should I go with a leaf-switch button?  I'm almost tempted to go with a Sanwa pushbutton, both because of soft feel and more reliable.  Dunno there...

YEEEESSSSSSSS! Of course!!!

heheeheh 

[Level42]

Sanwa on a real Centipede ??  I consider that cursing

100% agreed with RayB.

[Numbski]

Dunno, up until I got this thing, I don't recall the last time I'd used a leaf-switch joystick or button.  Holy cow they feel mushy.

Anyhoo, so Luigi...buttons?