Thanks but i believe you can forget my Boards, they are -really- destroyed.
But what i found out afterwards, are those A,B and C lines of CN11 on
the KLM-369 which switch the Input sources of the HD14051 and NEC D4051
8 Line analogue multiplexers.
What i believe is: The 8048 Main processor set those lines on KLM 369
and KLM 370. The (1)4051 send back over the DATA line the actual Voltage
of the choosen Variable resistor. The result voltage goes over the DATA
line of CN11 back to KLM-367 and the LM393 comparator.
So if the Main Processor DOES NOT set the Adress lines for the (1)4051
located on KLM 369 and KLM 370, you ill not get back any voltage on DATA
and so the Knobs won´t work! So in fact the 8048 would be responsible
for the defect (or one of those A-B-C-traces).
I thought the 4051 was a A/D-Converter but it is not true, he is
completely analogue. In fact you select on three adress pins of the 4051
a input pin, then he check the voltage which comes from the variable
resistor (cutoff, attack, decay etcpp) and send over DATA the Voltage
back to the LM393 located on the KLM-367.
Too bad that i found it out too late :) Also bad that i have no
schematics....
Greetings
Stef
Chromatest Pantsmaker wrote:
>----- Original Message -----
>From: st@rinass.de
>Date: Wed, 22 Jan 2003 12:15:56 +0100
>To: PolySix@yahoogroups.com
>Subject: Re: [PolySix] Common symptons of battery leakage damage?
>
>
>
>>I have exactly the same problem. Changing the two 74LS08, the 5514 RAM
>>(Replacement:2114) and the D/A-Converter below the RAM doesn´t help. I
>>
>>
>
>
>the problem could very well not be the chip itself! if the chip is socketed, check for continuity from the socket to wherever the trace goes... or you can trace from the chip pins. I was having a few residual problems with my p6 and they were all attributed to weak traces. I scraped, and soldered new wires/traces and it worked much better afterwards!
>
>good luck!
>
>