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Poly61 help or advice

Poly61 help or advice

2016-04-11 by studio_1a@...

I rebuilt my poly61 endcaps, so I removed the main and voice boards, reassembled the thing back together and worked fine. Afterwards I decided to replace all the tact switches, it worked fine turned it off. About 2 months later, turned it on and the assigner board and programmer boards switches are unresponsive, the displays constantly shows P5 / 61 and won't respond to any pushbuttons. The PSU +15/-15/+5 volt rails are good. Both programmer & assigner boards have voltage, checked all transistors and diodes and are good on both. 

Has anyone seen this type of problem before? could it be a CPU board issue? Looking at the prints, I can't seem to find whats common to both boards?


anyone has any ideas?

thanks in advance

Re: Poly61 help or advice

2016-04-23 by rpcfender@...

From bobgrieb <bobgrieb@...>

Both of the MCU's get the same reset signal. Did you check its state? If that signal is low, nothing will respond. Pin 4. 

Bob

Re: Poly61 help or advice

2017-04-02 by z7x76catnvcrna6acgnqrrxmku6o7mmirs43my3w@...

I have a similar problem.

Parameter and edit buttons do not work. Also the write button.
I can't get the write and tape enable buttons to enact parameter mode.

Voltages are all ok.

I would like to know if perhaps this might be a circuit, or even a connector (pulse) issue. The schematic that I found online is not clear enough for me to follow.

Background: when i acquired this Poly 61 it had a battery leak, so I replaced the Nicad battery to a Nimh and fixed the traces as best I could (following an unclear schematic). Currently the Poly will play a bunch of presets very well, the sound is good, but I would like to be able to edit the presets to create my own.

Any assistance would be most appreciated.Waz in Perth, Western Australia.

Re: [DW8000] Re: Poly61 help or advice

2017-04-02 by Bob Grieb

Maybe a brute-force approach would work for you?


Get a copy of the Poly 61 service manual and print the page that shows the main
digital board schematic. Take a multimeter and verify the connections on that pcb,
one at a time. As you check each one, color it with a highlighter. You can buzz out
the whole board in one evening, I think. Add wires to restore any connections that
have been eaten away by the battery leak.


The alternative is to use an oscilloscope to monitor the MCU reading the front panel
switches and see what's not working. But maybe you don't have a scope?


Bob

Re: [DW8000] Re: Poly61 help or advice

2017-04-03 by z7x76catnvcrna6acgnqrrxmku6o7mmirs43my3w@...

Hi Bob. Thanks for your reply!

Can anyone on the forum please help me out with a link to a clear pic of the connectivity trace pages in the service manual?
Board KLM-509 (around about page 16 in the manual).

It would mean that I could complete the job, and hopefully solve my Poly 61 dilemma!
----------

Clarification on where I'm at:

Traces that had clearly been eroded by the Nicad alkaline battery spill. I used white vinegar, distilled water and isopropyl alcohol to clean the board, and repaired the traces that I found that were visually, and/or multi-meter disconnected. I replaced the battery with a nimh battery with exact specs.

Next I found a photocopied version of the service manual and re-connected everything that was able to be read. The only page in the manual that I understood was where the traces could be directly followed, but it was a poor copy and I could not complete the job which was upsetting.

After checking and repairing the cable connections between all boards, I found 2x ic chips on the battery board that read +ve pin voltages of 4v instead of 5 (hex inverters). Also another that had flickering readings (a nand gate) which I assume will need to be replaced. These chips are on order (I had to guess at some of the specs. Fingers crossed). 

NB: I also found that the legs of half dozen or so capacitors in the left hand upper board (KLM-478 I think) have green coloured erosive material attached to their legs, so will look to replace them too.

I am looking to buy a desoldering gun next. I've not much success removing components (let alone ic chips) with solder sucker and wick. 

The power board readings are good, as are the 6x voice chips (reading 15v each). 
-----------

Any further help, gratefully appreciated. I would just really love to be able to edit parameters and load external sounds into my Poly 61.



---In DW8000@yahoogroups.com, <bobgrieb@...> wrote :

Maybe a brute-force approach would work for you?


Get a copy of the Poly 61 service manual and print the page that shows the main
digital board schematic. Take a multimeter and verify the connections on that pcb,
one at a time. As you check each one, color it with a highlighter. You can buzz out
the whole board in one evening, I think. Add wires to restore any connections that
have been eaten away by the battery leak.


The alternative is to use an oscilloscope to monitor the MCU reading the front panel
switches and see what's not working. But maybe you don't have a scope?


Bob