Hello,

I changed the PIA under the battery holder on Doctor Dude today and switch out the U25 for NVram. When I turn it on now I'm getting garbled characters on the left side display. See picture. If I press on the u41 chip or basically massage the chip, then I get what appears to be u41 pia failure, but then it also switched to Credits 6 after that. If I stop touching the chip it appears to go back to the garbled code like in the picture. What would be the most likely cause? The person who did it for me has been doing this kind of work for 40 years so I'm thinking the chip is bad?

So playing around with it again, the game will play, I just see nothing on the left side when it plays, right side display is fine. If I press the chip, I can get the left side to go although the letters are not quite right. Special when lit will be spelled slightly wrong etc.

EDIT: I don't seem to be getting the U41 PIA failure anymore, the game just either doesn't show left display or display is garbled or not showing correct letters, only seems to show display when I touch it. It does seem to show display when first turned on and then it fades out after about a second or so. Both chips were put in with sockets, don't know if I mentioned that.

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only a 6802 is socketed. this is a 6821

Ebay seller said he would send another. Just seems weird to me that the chip would act different when I touch it. Is that common for the chips or more indicative of a bad solder joint or something?

I don't know if it was a typo, but we replaced U41. I'm guessing U42 is right display and U41 is left display?

Well thats all greek to me. But the person who did a favor doing the soldering I sent it to him and maybe he understands it. I see that it appears that it eventually ends at the specific letters on the display, so if I figure out which letters aren't displaying properly, that would be the traces that have the issue assuming its not the chip?

BTW, the NVRAM I got from you works perfect.

Would this still seem like a trace issue if the whole left display goes blank?

Here is my chip, I've tried two of them. The first one the game will start half the time although I only see right display and left display if I press on the chip is garbled. Sometimes I get code for U41 pia failure. The second one I see nothing on the display. Second chip I confirmed is apparently bad, it just flashes Pia failure on diagnostics. Can anyone recommend a known good chip? I'm going to start with a known good chip and a good socket and try again.

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If one were to buzz out the connections, how exactly would they do that on this board?

Thank you, I have a voltmeter, but I'm a bit confused, aren't he traces under the board coating? Like I touch the pin on the socket/PIA chip and then touch what?

I'm thinking socket too, but I can't really rule out the stupid chip since the second one sent definitely appears to be bad when the guy said he was testing that one before sending. I'm thinking of waiting for the westerndigitals to come into stock as mouser and try one those chips. While I wait I'll try to trace this stuff out.

I noticed under the battery holder, the traces don't look great under the left most battery however considering we never touched those and the game worked fine before we swapped out the chip, I'm guessing those couldn't be the issue?

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I don't disagree with you, I just have a hard time understanding why it all worked fine before we removed this chip. My best guess at this point is a problem with the socket, unfortunately I have to wait for a new chip and I have no idea when mouser will get more in.

Are the Jameco 6821 chips good? I'm just trying to make sure I get a good chip this time and trying to go to one place to get the socket and chip so I'm not paying shipping twice.

or has anyone ordered for this person?

ebay.com link: itm

Guy wants me to try new chip first before he resolders new socket so I won't be popping it out again for a little bit. Considering he is a friendly neighbor doing it all for free, I can't really complain. I'd be happy to get pics once its out again which likely will be after I put the new chip in and it still doesn't work.

Can anyone confirm on either of these? Quite a pain to ship these things back if they don't work if they will even take them back. Being out of work, I really don't have extra money to burn at the moment.

I got new chip from Jameco today. This chip is flashing U41 pia error via the diagnostic LED same as the second chip from EBAY did. First chip from Ebay game would start and have right display but left display was garbled. Since 2 out of 3 chips say U41 pia error and the two that say that error are from different sources, I'd have to assume that the chips are good and something else is wrong? I have a new socket from Jameco to put in when I get a moment.

So finally got to have the new socket put in. Socket seems nice, solder job seems nice, yet I'm getting no display and the LED is flashing 5 times indicating pia 41 is bad. Does that mean I need a new pia chip? I attached pics of socket and solder job.

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You can see from the pictures there is only one bridge and my understanding those pins are supposed to be joined together.

Also, I could probably figure out how to check the traces, but it concerns me that before with the old socket, the displays were lighting up and now both displays are completely dead, does that appear normal if U41 is bad?

okay, so with my limited ability I did some testing. Chip is definitely getting ground and plus 5 volts. Testing the PIA chip from http://techniek.flipperwinkel.nl/wms11/index2.htm#cpuled appears to show the chip is good. However, when testing pins 2 3 4, they are getting continuity to the J22 connector but I can touch pin 2 on the PIA and I get continuity on any pin of the J22 connector, same for the other pins. Any ideas on that?

I tried to reseat the chip, no difference. Chip in or out of the game gives me the same thing. One tone. 5 volts lit up, 5 blinks from diagnostic led and blanking led flashing.

bump, anyone have any ideas?

Yes, I'm sorry, I forgot to take pictures as he removed it, we did look at the traces and they appeared fine. Guy doing it said 100% no traces were lifted.

At any rate, as I posted, I did start buzzing out the traces last night an I'm getting continuity from one pin on u41 socket to all pins on j22. Does that make sense?

I'm also getting same exact startup error with chip in or out.

So the traces are buzzing out now, but they buzzing to like completely different pins then what I believe the schematic is sayings. Like pin 40 should go to pin 15 j21 and its like pin 9. Pin 3 is going to pin 18 unless I"m completely misunderstanding the markings on these things.

I'm very concerned about the display not lighting up, before it was lighting up saying u41 failure or garbled characters, now its completely dead. It appears one of the high voltage power supply fuses has blown. It appears its 8a 250v. Are these available any place locally?

I did plug turn on the machine after the new socket was installed with all connectors and forgot to plug the connector in from the power supply to the mpu. Could have have caused the fuse to blow?

anyone have any ideas why the traces aren't matching up to what I believe they should be?

Guy who soldered it had a fuse for me for the 100 volt section. replaced that and now I have the same u41 failure code flashing on led, but also the left display is flashing basicallys 0's when ever the blanking light blinks.

Yes, definitely on the U41 and I assume so on the J22 connector but they aren't matching up to what the diagram says they should be on J22.

I apologize to whoever I stole this image from on the forum. Can someone tell me how the pins go on J22. I'm pretty sure I'm counting them right.

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ah okay, so I assumed that it went pin one to pin 13 and then pin 14 to 26 in each row. So if thats the case with j22. How come U41 goes 1 to 20 in one row and is completely different than this?

okay, well with new info, pins seem to be tracing out correctly. I ordered the western digital chip from mouser so hopefully when it gets here, problem solved.

I had 2 other chips and I had to send them back to the vendor, so I currently have one chip here and it appears to be bad. Unfortunately I don't have a stack of them lying around to test another one.

So maybe try being helpful, which traces would I check to confirm it can access the PIA?

Yes, my board doesn't look like that, that picture was just to figure out if I was wrong about the pins and I was on J22.

Honestly, nothing was wrong with it, it worked perfectly fine, but there was a slight bit of corrosion on one or two of the pins on the U41 and I was told I should fix it so I did. Believe me, if I could go back in time, I would have just left it alone and not said "I do" either

Thats a problem with this thread, Post 16 is not my board, someone else posted in here as well.

So new chip is in, same error message. Clearly something got messed up in the soldering job. I will try to check the traces again before seeing if I can get someone to fix it. I'm trying to find someone local and unfortunately its not that easy. So just to make sure I"m doing it right, when I check the traces. Should the board be unplugged and what about the nvram, do I need to take that out as well?

I am up to pin 23, all check out, will finish the rest hopefully tomorrow.

Got through 27 now. 24 is definitely not working. do I have to jumper every place it goes to?

EDIT: Got through all of them, definately pin 24.

so I looked and the pia pins that are supposed to connect are fine and the u14 I believe it is connects fine to the other pia's. So I just need to run a jump wire from pin 24 on u41 to one of the other pias correct?

Unfortunately while that is within my skill level the only iron i have right now is no where near small enough. Hopefully the person that has been helping me can get this jumpered soon. Tentatively Friday and this should be good to go.

jumper wire added, it works now. I was nervous at first when I started it up as the left display was scrambled but I pushed down a little on the pia and now its all good.

It does seem to be humming more than it did before. Anyone have ideas on that, all screws are tight on the board.

Honestly it was really only one part being the western digital pia chip and I wanted that anyway as I prefer the new source and they were out of stock at the time. plus I needed a fuse anyway.