Author Topic: Hantarex Polo Revisited... (Read 9613 times)

gokun · « **on:** October 20, 2008, 05:31:21 pm »

Ok, if you all recall, I had originally had a pincushion problem with this one which grantspain helped me remedy...
So, having just finished my new monitor test rig thingy(yay!) I decided to use that same monitor to test it since it's already not in a cab, etc. Bare in mind I hooked it into a cab back when I originally fixed it to verify it was working and it was...also note; plugged a 25" nanao monitor into the new rig and it was perfect. Also, since that last fix the monitor has basically just been sitting on a shelf waiting for a home...anyways, so I plug it into my new test rig and....
the pincushion problem is back-doh!! This monitor does not have the pincushion adjustment board.

Ok, so I re-read the old thread to make sure my memory of it was correct, and then I go ahead and replace the east and west diodes since that is what fixed it last time(and I always order more parts than I need so I had spares from last time too)....anyways, after replacing the diodes this time the pincushion effect is still there....weird...test the diodes and they are fine as far as I can tell(not to mention brand new)....

so, based on the previous discussion, I'm wondering if perhaps this monitor DID at some point have the pincushion adjustment board, and whoever removed it just did a really good job of desoldering it so it's hard to tell....really, the adjustment board is the only other thing I can think of....all the caps have already been replaced from last time and the diodes for east west, as I mentioned, have been replaced again as well...but then again, if you check the pics in the old thread an area nearby these diodes is where part of the mystery repairs were done, so I suppose there could still be a problem there maybe? although I don't really understand why it would just suddenly appear like this...anyhoo, moving on...

so I suppose my question is...would there be any explanation other than the pincushion adjustment board that could be causing this? I've read some threads related to this, which have some things to look at, but they were all for smaller monitors like the 25" model and I'm not sure if the part numbers, etc. would match up with this 33" I have....so actually that makes 2 questions as I would like to know the answer to that one as well...
if the part numbers match up with the smaller monitor versions then I have some more things I can test based on the other threads I've read...if not, then I would need some help in determining which parts to check on this one...
although I still somehow feel like I could adjust this out with the adjustment board...is that crazy?

As always, any and all help is greatly appreciated, so TIA!
P.S.
I will post a pic later tonight-my wife's camera memory is full and I'm afraid to delete anything off it to make room without her being here to supervise...so I have to wait until she gets home tonight before I can take a pic, but will upload one then...although I'm sure you all already know full well what a pincushion problem looks like

grantspain · « **Reply #1 on:** October 20, 2008, 05:52:01 pm »

you may have some damage to one of the traces,it will be around those diodes somewhere-check continuity in that area

gokun · « **Reply #2 on:** October 21, 2008, 12:18:19 am »

here to save the day for me again grantspain-THANKS!! I will check on that over the next couple days and let you know what I discover.

[EDIT]
I'm in the process of checking this out now...there was some bad weather in the area for severa ldays and lotsa static in the air, and I'm very prone to collecting a static charge for some reason, so I figured better safe than sorry and decided to wait until I couldn't feel the "tingle" anymore.

gokun · « **Reply #3 on:** October 27, 2008, 11:38:14 pm »

OK, been checking the traces around the diodes as advised and I have a question...I believe I already know the answer, but I would greatly appreciate hearing from someone else who knows more than me(which is just about every reg on these forums-lol)...at any rate, using the following picture as an example(and it IS just something totally made up but it gets the point across so bare with me):

the light green represents the trace in question, and the circles represent the solder points within it. simple enough...
ok, so...if all the points on that trace give continuity with one another except for the one in blue, would that mean the blue one would need a jumper wire on it to restore continuity? generally speaking I mean....reason I ask is because I have found that situation on one of the traces from one of the pincushion diodes...all other points on the trace have continuity with one another except for one...so I'm wondering if that could be the issue possibly...I tend to think that even if not the issue, I should at least have continuity to it since all the others on that trace have it...but of course, I wanted to ask before I went and did anything that might muck it up worse(I've been down that road before and it's no fun let me tell you)...
so what do you think? am I on the right track(horrible pun not intended) or way off base? or do you need more info like what part is connected to the solder point in question? Let me know-thanks!
I'm making the effort but the learning curve on monitors is steep so once again, let me just say I greatly appreciate you guys helping and being patient with me. and my apologies if this is a stupid question too.

grantspain · « **Reply #4 on:** October 28, 2008, 03:06:23 pm »

let me look at one of my chassis to just check what you are saying but if the component through hole has lifted then that would cause your problem

gokun · « **Reply #5 on:** October 29, 2008, 08:27:53 pm »

thanks grantspain!

I did some checking myself and picked 5 random other traces on the board to check as a comparison, and all had continuity between all points...so I think I'm safe assuming the same in the case of my earlier question with the one connected to one of the pincushion diodes.

Also, while doing this, I just by pure luck noticed a cap that was in backwards(one of the few i did not replace...go figure!)...so I removed it and replaced it with a fresh one which follows the orientation marked on the board...so hopefully that will do something useful too.
at any rate, I just need to plug it up and test it at this point, which I will let you know the result of...with any luck it won't explode in my face at least. ;p

[EDIT]
Picture looks pretty except for the pincushion problem...darn it...guess I'll keep looking in the meantime...could one of the ics cause this maybe?

[EDIT2]
actually I'm wondering if the bdx chip could be involved somehow...I found some info on a polo 2 with exactly the same issue(e.g. replacing pincushion diodes didn't fix) and replacing the bdx and a resistor nearby it fixed the problem...so I'm wondering if the same could work for me...any thoughts?

grantspain · « **Reply #6 on:** October 30, 2008, 03:42:13 pm »

bdx53c transistor do you mean?

gokun · « **Reply #7 on:** October 30, 2008, 08:01:45 pm »

Yes-that's the one! in this case a bdx53a and i'm thinking that a 2sd1192 would be a suitable replacement?

I finished checking all the repairs and traces btw and everything else checks out, so I am thinking of ordering a couple of these transistors if the 2sd1192 is a suitable replacement...i can't seem to find the bdx53a anywhere and that's what it has in it now...would a 53c work? i noticed in the specs that it was like 100v compared to the like 60v 53a so i was thinking i couldn't use a 53c...but i did see loads of those while hunting for the 53a...

Quote from: grantspain on October 30, 2008, 03:42:13 pm

bdx53c transistor do you mean?

grantspain · « **Reply #8 on:** October 31, 2008, 03:44:38 am »

yes i have had a fault in that circuit once that caused the pincushion problem,i also changed T117 bc5588
i am sure i used a bcx53c to replace the a but i will check because i know where that chassis is,i will let you know today

gokun · « **Reply #9 on:** October 31, 2008, 09:25:09 am »

outstanding! thanks!
I will check on that bc5588 in the meantime...

grantspain · « **Reply #10 on:** October 31, 2008, 02:30:58 pm »

sorry no chance today,i am under a bit of pressure at work and lost track of time-should be o.k tomorrow to check

gokun · « **Reply #11 on:** October 31, 2008, 05:10:39 pm »

no worries! whenever is convenient for you is fine with me-thanks!

grantspain · « **Reply #12 on:** November 01, 2008, 01:33:56 pm »

one of mine has a bdx53c installed

gokun · « **Reply #13 on:** November 01, 2008, 05:21:44 pm »

good to know; thanks!
btw where is that 5588 located on the board? I can't seem to find it...

grantspain · « **Reply #14 on:** November 01, 2008, 05:31:58 pm »

T117

grantspain · « **Reply #15 on:** November 03, 2008, 11:30:26 am »

confirmed bdx53c is a direct replacement
another thing to check is the bridge coil (L107) it has an adjustment that can affect the pin cushion

gokun · « **Reply #16 on:** November 03, 2008, 07:03:47 pm »

killer! thanks as always; I will check that as well-should have an update on my progress by tomorrow or so btw

[EDIT]
(you know I can't resist playing with this stuff-you guys got me hooked!)
interestingly enough, a quick glance at l107 shows me that the top of it(the place where it looks like you could adjust with a flat tip screwdriver) is broken on one side...so maybe someone played with it in the past? don't think it would have just broke off the way it is on its own...so that brings me to the question of should I try to adjust it?
It looks like there is still enough of the top left that I could...should I try adjusting it while powered on so I can see the results as I adjust, or should I adjust while it's off then power on to see results? or should I muck with it at all? let me know; thanks!

grantspain · « **Reply #17 on:** November 04, 2008, 12:49:53 pm »

yep sounds like the coil has been messed with,normally bad techs use this coil to help bring the width when there is a width fault
my guess is that in the past the bdx53a or east/west diodes went faulty and the bridge coil was used to pull the width in and thus broke in the event
i would suggest adjusting the bridge coil and this is something you can do whilst power is applied as long as you use a mirror and are careful

gokun · « **Reply #18 on:** November 05, 2008, 01:02:04 am »

...sigh...i just can't win with this thing...
ok so I replaced the bdx transistor and the result was that the picture was a little too big for the screen, particularly from lefft to right...fiddle with the adjustments on the remote board and they work, but don't adjust it enough...i notice that turning down the brightness and contrast seems to make the screen a little smaller...i can move the image far enough to the right to see the left edge of the image and it appears as though the pincushion deal is mostly gone...it was originally much worse on the left side and now wasn't so that was good...also i don't seem to recall it followed the image before either, but rather was always there at the edge of the screen...not 100% on that though...can't find my darn notes...
since the remote isn't doing it for me i try adjusting the coil slightly one way then the other...no noticeable difference...try moving it further one way then the other...not noticeable difference...
now here's the fun part...i had noticed a slight whine about a week ago, but didn't think much of it at the time...noticed it was louder when began testing tonight...then, surprise surprise, my flyback blows out on me...doh!! at least that is what I believe it to be right now...letting it sit a while before I muck with it...so just can't win...right when it seems i'm close to the solution to one problem another comes up...so now i'm back waiting for parts again once all is said and done...anyways, so what do you think about the pincushion deal in the meantime?

grantspain · « **Reply #19 on:** November 05, 2008, 01:41:07 am »

you are getting some real bad luck here,check +145vdc at r227 and make sure the hot is o.k

also i wonder if someone has messed with rv101 adjustment

gokun · « **Reply #20 on:** November 05, 2008, 10:12:38 am »

ok will check that-thanks!
yeah, this one has turned into quite the little project for me...but what the heck, I'm learning so that's at least one good thing that comes of it...
also, i would dare say, based upon all i've seen that's been mucked with thus far, that if there were something that could be adjusted some way, that numbskull adjusted it...lol
at any rate, i got some more checking to do before i order any parts, so will finish that up tonight and get some parts ordered hopefully...then we can continue once everything is back together again...in the meantime feel free to share any thoughts or theories you have. thanks!

gokun · « **Reply #21 on:** November 05, 2008, 10:28:56 am »

one more question....(trying to get my backup plan ready as well)...
would a Wells Gardner WG 2775 27" K7500 Color Monitor Chassis work as a replacement here?
reason i ask is because I can probably get that chassis(working) cheaper than a new flyback...anyhoo, might not work, but thought I would ask just in case...let me know-thanks!

grantspain · « **Reply #22 on:** November 05, 2008, 11:45:23 am »

hmm,not sure-if the k7500 has a similar yoke reading and the neck is the same then i don't see why not
i am not a massive fan of swapping chassis of different types as you can get mismatches on the filament voltage and yoke variences

are you sure your flyback has crapped out?

gokun · « **Reply #23 on:** November 05, 2008, 12:04:03 pm »

actually no; not 100% sure yet to be honest...I plan on checking it good tonight after work...was too paranoid of getting shocked to play with it last night...will let you know for certain onight some time...
as for the chassis, you make a valid point I had not thought of...plus, i'm not going to learn much about repairs if I just replace the chassis with one that already works...so I guess I will just stick with this one for now...thanks as always for sticking with me! I really really appreciate it a lot!

Quote from: grantspain on November 05, 2008, 11:45:23 am

hmm,not sure-if the k7500 has a similar yoke reading and the neck is the same then i don't see why not
i am not a massive fan of swapping chassis of different types as you can get mismatches on the filament voltage and yoke variences

are you sure your flyback has crapped out?

gokun · « **Reply #24 on:** November 06, 2008, 10:44:48 am »

sorry for the delay...took me a little longer than I thought to get through all the checking...
ok, so, as far as I can tell thus far, the HOT, etc are ok and the board does have power going into it at the plug...r227 itself also seems ok, although I am not 100% sure i checked the 145v there correctly so still unclear on that(gonna try again after work tonight to make sure)...even switched monitor back on a couple times to see what might happen...and basically nothing does...you hear one quick click then nothing happens at all(no static sound from the degaus thingy, etc no neck glow, no signs of life in general...
also, thinking back, I believe the noise I heard before it went out had been coming from the flyback itself(well, near as I could tell at the time...that was where it was loudest at least)...
of course testing transistors with a crappy multimeter isn't a perfect science, so I might replace the hot just to be safe since I believe I have a spare anyhoo...I also double checked all the repair areas again just in case, and all seems to be holding up...didn't find any new breaks, etc either...all the caps seem to be fine...no obviously blown resistors, etc...
I'm going to go back over it tonight though just to be sure and verify the results I got last night...so whatcha think? sound like the flyback to you? (I found one for about $30 but wanted your opinion before I actually order it)

grantspain · « **Reply #25 on:** November 06, 2008, 11:09:52 am »

flybacks do crap out on polo monitors so its possible,i would read 145v at tp6 to chassis frame first(dc range)-be careful,scary stuff
if its missing then check d116
if its ok then check at one side of r227 and also r219(i think its around +132v after r227)
it would be wise to check continuity of the bride coil L109
also important is that you make sure any insulation sheets behind the bu508a and bdx53c are still in place
normally a bad hot will read dead short collector to frame(centre leg)

gokun · « **Reply #26 on:** November 06, 2008, 11:18:48 am »

awesome info as always! wil let you know the results of my testing

gokun · « **Reply #27 on:** November 14, 2008, 08:13:16 pm »

well, took me a while to get back to this...unfortunately real life comes calling every now and again...anyhoo, here is what I've found:
fuse is ok
D116 appears bad
D105 appears bad
the HOT appears bad
zd101 is possibly bad(not sure i'm testing it correctly)
I set my 2 multimeters to 250vdc and check TP6...I get 0-4.1 as my reading and it flucuates pretty wildly on both meters?
continuity around L109 seems fine...
all caps seem ok...
I cannot find the following which according to my notes I need to check:
r103, r219, r227 (weird thing is I think i found this one at one point now can't-lol)
I looked and looked...then had a friend look...then had my wife look...then looked again myself...I just can't seem to find the darn things anywhere...also notes say I could not find ic101 either...hrmmm....
not entirely sure how to properly test the flyback...but I can tell you that there is a noise when you turn on the monitor(maybe the degaus?) but no gratifying static sound and of course, no pic on screen....
so there ya have it...
I guess I would need advice on how to properly test the zd101 and flyback, and help finding those missing resistors,etc...and of course any other help you care to offer...thanks as always!

grantspain · « **Reply #28 on:** November 14, 2008, 08:24:03 pm »

to test any diode you need to remove one side from the circuit board and use a diode test to read-you should only read one way

to read the hot set you meter to beep test and read the centre leg to the heat sink,dead short means the hot is bad

gokun · « **Reply #29 on:** November 15, 2008, 03:26:19 am »

thanks grantspain as usual....HOT is bad for sure then...but I have spares, so no biggie...I will double check the diodes tomorrow just to be safe; I was mainly just thinking I had to test the zd101 different becuase it had the z in front of it(in case you couldn't already tell, it's easy for me to get confused)...anyways, it's like 2am here now and I'm gettin tired...I know, I'm a wimp!

will also take another look for those pieces i couldn't find tomorrow while i'm double checking the diodes...maybe since I haven't been messing with it as much lately, having a clear head will help me locate em...sigh...it's a good thing I don't actually need this monitor for anything right now-lol! makes for a good learning project though.

gokun · « **Reply #30 on:** November 15, 2008, 03:04:05 pm »

ok, so I pulled out my analogue multimeter becuase I read the digital ones aren't that great for testing diodes...
I remove one leg from the board, then test on 1k ohm and 10 ohm....with the multimeter leads one way I get a reading...reversed I get nothing...this is on both ohm settings...sooooooo....that would mean they're actually ok wouldn't it?
Also verified the HOT is bad(still haven't replaced it yet) with analogue...
I found r219 I believe(the numbers are gone in this area but 217 and 220 are nearby and I don't see 219 anywhere else...it tests ok....still cannot find r103 and r227...although oddly I can find 102,104,226,& 228...sigh....I just suck I suppose...

also re-checked tp6 with this meter on 250vdc and reading is still incredibly low(although does not fluctuate wildly like on the digital multi-just hangs at a really low reading, which is just to say it barely moves at all)...
what else did I do.....hrmmmm.....I think I killed too many brain cells in my youth-lol...
re-checked a couple caps including c112(read somewhere that i should)...all ok...
I forgot to recheck zd101...will do that this evening after I get done being my wife's personal beotch errand boy.. ;p
what else....l109 area continuity still reads ok(although it may be worth noting that is the area in which I had to add a wire in to get continuity back between a couple of the points as mentioned earlier)...
I was also just eyeballing the flyback and didn't see any obvious breaks, melted areas, etc....
checked all the insulation areas I could find behind stuff and all seems to be still intact, etc....
I'm still aggravated about r227 specifically because I had found it at one point, and now I can't seem to locate the darn thing again...it's really driving me crazy...but I digress...
at any rate, let me know what you think, anything else I should check, etc. Thanks!
(btw sorry if I'm being a nuisance)

[EDIT]
I just noticed while re-checking tp6 yet again...feel pretty good that I did it correctly this time...anyways...what I noticed was that the reading does still fluctuate on the analogue it's just harder to notice as the reading is very low to begin with and the fluctuation is slight...now here's the thing I noticed that I think is important...I heard a very(and I do mean VERY)soft ticking sound coming from the flyback area(which is also where the hot is of course)...now this ticking in addition to being very soft, the ticking is very regular, and the fluctuations match the rythm perfectly...literally every time it ticks the meter will jump slightly...so would that lead us to believe it could just be the hot? Anyways, my wife is waiting for my punk butt so gotta run, but just wanted to throw that last part in before I was in disposed for the rest of the afternoon.

grantspain · « **Reply #31 on:** November 15, 2008, 03:41:35 pm »

does you hot have a metal back?

gokun · « **Reply #32 on:** November 15, 2008, 03:43:42 pm »

Quote from: grantspain on November 15, 2008, 03:41:35 pm

does you hot have a metal back?

nope

grantspain · « **Reply #33 on:** November 15, 2008, 04:00:39 pm »

hmmm,remove the side of L103 closest to to tp6 and then read from chassis frame to the soldered side of l106-you should get a stable 145v

gokun · « **Reply #34 on:** November 15, 2008, 08:10:40 pm »

Quote from: grantspain on November 15, 2008, 04:00:39 pm

hmmm,remove the side of L103 closest to to tp6 and then read from chassis frame to the soldered side of l106-you should get a stable 145v

I don't think I understand...l106 is soldered in on both sides unless I remove one side of it myself(it looks like a blue resistor if that helps)...that being said, when I measure the voltage on the side of l103 that is still soldered(desoldered the side closest to tp6 as instructed), I get about 174v on both analogue and digital meters...it is stable reading and does not fluctuate at all...could you please clarify what you mean for me to do with l106? thanks!

grantspain · « **Reply #35 on:** November 16, 2008, 06:06:49 am »

sorry meant L103 not 106,i think i was tired
o.k it seems like the problem is either the flyback or the horizontal output stage

gokun · « **Reply #36 on:** November 16, 2008, 12:46:49 pm »

ok, so let me ask you this...if I were te replace the flyback and hot but another piece in the stage was still bad, would it blow out my new flyback? (just don't wanna chance blowing out a brand new one). thanks!

grantspain · « **Reply #37 on:** November 16, 2008, 01:03:29 pm »

never seen a flyback killed by another component,if you can give until tuesday i will double check some of my archive notes at work concerning some other checks to make

grantspain · « **Reply #38 on:** November 16, 2008, 02:56:50 pm »

hang on a mo,what's the exact number of the hot you are using?

gokun · « **Reply #39 on:** November 16, 2008, 04:54:51 pm »

at the moment it still has the bu508a in it...
and yes, I can happily wait until tuesday for that info you mentioned.

grantspain · « **Reply #40 on:** November 16, 2008, 05:07:56 pm »

a bu508 a has a metal back,you sure it not a bu508af or else?
if it has a metal back then you must install a insulation sheet between the back and the heat shield

grantspain · « **Reply #41 on:** November 17, 2008, 11:11:10 am »

desolder pins 1 and 3 of the flyback transformer(make sure they are completely desoldered and not touching the trace)so it is isolated from the circuit
then use a 40 watt light bulb with crocodile clips connect one side the the chassis frame and the other to R227 nearest pin 3 of the flyback
when you switch on you can meter the b+ at r227(bulb side) and it should read around 110-115v dc steady
if it reads really high then there is a crack on your board and is normally around any fixing point or where the heat shield clips in
if it reads good then for sure its a dead flyback

gokun · « **Reply #42 on:** November 17, 2008, 02:45:37 pm »

Quote from: grantspain

a bu508 a has a metal back,you sure it not a bu508af or else?
if it has a metal back then you must install a insulation sheet between the back and the heat shield

not as far as I can tell, but the writing is faded and hard to read...I will just desolder it to get a better look tonight after work.

Quote from: grantspain

desolder pins 1 and 3 of the flyback transformer(make sure they are completely desoldered and not touching the trace)so it is isolated from the circuit
then use a 40 watt light bulb with crocodile clips connect one side the the chassis frame and the other to R227 nearest pin 3 of the flyback
when you switch on you can meter the b+ at r227(bulb side) and it should read around 110-115v dc steady
if it reads really high then there is a crack on your board and is normally around any fixing point or where the heat shield clips in
if it reads good then for sure its a dead flyback

Will do! just gimme a couple days to get it done. Thanks!

gokun · « **Reply #43 on:** November 18, 2008, 08:38:24 pm »

Quote from: grantspain on November 16, 2008, 05:07:56 pm

a bu508 a has a metal back,you sure it not a bu508af or else?
if it has a metal back then you must install a insulation sheet between the back and the heat shield

ok,I removed the HOT and have it in front of me as I type this...the only markings on it say BU508A and underneath that it says S0010. And it does not have a metal back. There was, however, a nice little black spot(burn?) on the insulation behind it when I took it out if that helps at all.

At any rate, still working up my courage to test the flyback; will post the results as soon as I do. Thanks!

Kevin Mullins · « **Reply #44 on:** November 18, 2008, 09:07:34 pm »

You need to test that HOT ..... forget about testing the flyback.

gokun · « **Reply #45 on:** November 19, 2008, 10:16:51 am »

Quote from: Kevin Mullins on November 18, 2008, 09:07:34 pm

You need to test that HOT ..... forget about testing the flyback.

Already did several times...it is bad. But unfortunately there is more going on with this one than just that 0_o

grantspain · « **Reply #46 on:** November 19, 2008, 03:25:33 pm »

a faulty flyback can cause the hot to blow constantly,also there has been instances of bad batches of transistors as well
the light bulb test should prove where to look

gokun · « **Reply #47 on:** November 22, 2008, 10:03:55 pm »

ok, finally got back to this...found r227 again(and felt really stupid for not being able to find it before...sigh...it's only like a HUGE white box screaming "look at me! look at me!"....but I digress)....
where was I.....oh yes....
so was getting ready to do the last test you recommended with the flyback...got pins 1 & 3 desoldered really good and prepared my lightbulb with alligator clips....
but since I had relocated r227 finally, I decided to test it with a fresh head....turns out it is bad....no biggie as I found replacements available that I can order....but it raised a question in my head I would like to ask you....
Is it safe to do the test with that resistor being bad? Also would I get an accurate reading if I did? I'm assuming no on both, but would like to know for certain before I do anything. Let me know; thanks a bunch!
oh! one last thing...that is a 10W 4ohm resistor, correct? The writing on it is kinda crappy and hard to read(seems to be a trend on this monitor) and I still suck at reading the schems...thanks again.

grantspain · « **Reply #48 on:** November 23, 2008, 06:04:02 am »

its a 10 watt 4.7ohm,never had one go faulty myself but had a lot of polo with trace breaks around this resistor
you can safely check the chassis still its just if the resistor is open circuit then you will need to read the B+ before the resistor and you will get a high reading

gokun · « **Reply #49 on:** November 23, 2008, 01:44:08 pm »

k; thanks! will let you know the results this evening sometime...

gokun · « **Reply #50 on:** December 06, 2008, 07:07:40 pm »

ok...holidays are keeping me too busy...sigh...but finally got back to this again...
so here we go...
desoldered pins 1 and 3 of flyback, reinserted hot(you'll recall I had removed it to verify the numbers on it, etc-this is the same bad one as before), then connected my lightbulb up(I used a 60w bulb actually...bulb in socket with gator clips...clip the black to the chassis frame and the white to r227 nearest pin 3 on flyback as advised)...powered on and went to take readings...
upon power on you can still here the initial sound(the deguass? that's what it sounds like...) then of course nothing...so start checking for b+ at a couple spots I had traced to be in front of r227(you'll recall r227 is bad also) and oddly enough, I get nothing at all...so just to be thorough tried it on the blown r227 too....nothing at all...
Also it has stopped making that faint ticking I mentioned in an earlier post...so I dunno...
I'm thinking I've missed something or took the readings wrong or something...
whatcha think? would a pic of my setup help at all to make sure I'm connecting the bulb properly, etc? I can provide one if you want...
...totally open to ideas, suggestions, etc and as usual have no intentions on giving up on it just yet, so totally willing to try whatever I need to...thanks!

grantspain · « **Reply #51 on:** December 07, 2008, 07:02:46 am »

does the lightbulb light up,if not then you need to trace the b+all the way back,meter at tp6 for +145 dc-if not present you need to check d116

gokun · « **Reply #52 on:** December 08, 2008, 02:02:53 am »

ok, no light up on bulb and voltage not present at tp6...will check the diode and let you know...it's late now unfortunately and I'm getting the damnable flu it seems

....so anyways, gonna sleep tonight and finish up with checking that diode tomorrow. thanks, as always, for the input!

grantspain · « **Reply #53 on:** December 08, 2008, 05:29:13 am »

2 very important things to remember,
1-diodes should be read out of circuit(lift one leg from the trace)
2-the primary stage of the power supply is deadly so be real careful around there

also double check you have isolated the flyback completely from the traces and the light bulb meters continuity across the circuit

atm this looks to be a missing +145 dc voltage
you will also need to check +85v at TP7,+27 v at TP8,+15v at TP9
also important to note that some revision of polo chassis had a safety resistor installed on both the +145 and +27,check if this is the case with yours-most likely a flame proof 1watt 2.2ohm-if this is the case and it is open circuit YOU MUST install the exact same type or you may get a minor fire

make sure you meter is set at DC volts,i am sure you know.

gokun · « **Reply #54 on:** December 09, 2008, 05:43:12 pm »

outstanding! lotsa stuff to check...will let you know my results soon as I get a chance to sit down with it again.

gokun · « **Reply #55 on:** March 05, 2009, 10:46:37 pm »

Wow was away from this one for quite a while....sorry it's been so long, I been caught up with other crap unfortunately...sigh...hate it when that happens....anyways....long story short, I ended up replacing(including stuff from the original problem probably as my notes kinda suck in retrospect)...

All caps were replaced...r227 and a couple other resistors replaced(r227 was the only one that was not the 'regular' kind), replaced the HOT, replaced east/west diodes, replaced the flyback(found one for $20 shipped-too good to pass on), and I "re-fixed" some of the repairs that were in place when I got it, and I did find a broken trace eventually too while doing the re-fixing so took care of that while I was there. What else....hrmmm...I seem to recall doing something else but it's not in my notes...at any rate, I think I covered the main stuff I did...oh wait! I adjusted the bridge coil thingy! that was it I think....so yeah that's probably it because the top of it was broke and I remember getting paranoid while adjusting because my hand was uncomfortably close to that damn anode wire...basically just threw parts at it, which I realize is not ideal, but that's still the novice level I'm at...so after all that, it worked again...

and then my wife made me get rid of it because I had no use for it anymore...sigh...so after all my troubles I end up giving it to a friend who is trying to build a mame cab from scratch...so there's my good deed for the month-lol!

At any rate, I learned a LOT more about troubleshooting and such so I consider it overall a successful project despite all the problems I had...so now I'm looking around locally for another broke one to play with(but something much smaller this time so my wife don't get so mad about it being on the floor for 3 months-lol!)...I figure the only way I'm gonna get better at this stuff is to keep doing it.

And finally, I would once again like to thank grantspain for all his help this time, as well as every other time I've had a problem with a monitor. Could not possibly have learned or done this much without your help dude so many, many thanks!
PS
I did at least play 1 game of turkey hunting on it before I gave it away...it actually callibrated better than the monitor that came with the turkey hunting cab-lol! so at the end of the day I guess I did get to really enjoy the monitor once before it left me.

grantspain · « **Reply #56 on:** March 06, 2009, 05:48:09 am »

well all that work and you have to get rid of it,on the big positive side you have learned a great deal about monitors-that in itself is priceless
glad it worked anyway


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