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| Previous Messages | Posted By
nc513 on 2022-04-04 03:11:57
| Re: Plus/4 310163 board with TED and CPU inserted the wrong way
Absolutely no signal (through the A/V port of the Plus/4, on my TFT display) and the TED and CPU were cool to the touch. If I remember correctly ... :P
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Posted By
JamesC on 2022-04-03 22:26:08
| Re: Plus/4 310163 board with TED and CPU inserted the wrong way
"After installing the chips in the correct orientation, the board outputs a black screen."
What colour was the screen before you rotated the chips?
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Posted By
nc513 on 2022-04-03 18:17:14
| Re: Plus/4 310163 board with TED and CPU inserted the wrong way
Thanks. Yeah, I guess I might have to bring my dusty old scope out of storage.
I don't currently have access to any other Plus/4 boards, or even a C16. Might have to do something about that.
Just for the heck of it, I've desoldered all 8 DRAM chips as well as the multiplexers U9 and U10. They all tested good in my C64, so I installed IC sockets on the Plus/4 board and reinstalled those 10 chips. I've also removed the ACIA. The symptoms haven't changed one bit.
Brute force repair might not be the best strategy for this particular board ...
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Posted By
gerliczer on 2022-04-03 03:54:40
| Re: Plus/4 310163 board with TED and CPU inserted the wrong way
First, you should test those two chips in working machines to see if they survived the ordeal. Third suspect to cause blackout would be the PLA. You should check that too. Go to Bo Zimmerman's Commodore Archive and read the Plus/4 Service Manual for further steps. Tape is powered form a separate supply circuit. You should check that too with the help of the manual and the schematics. Those can be found there too.
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Posted By
nc513 on 2022-04-02 17:38:47
| Plus/4 310163 board with TED and CPU inserted the wrong way
Hi,
I've just received a PAL Plus/4 310163 board with TED and CPU inserted the wrong way, i.e. rotated 180 degrees.
After installing the chips in the correct orientation, the board outputs a black screen. Reset works (pin 40 of the CPU goes high) and I've got 17.73 MHz at pin 14 of the TED.
I've got 5V DC at pins 2 and 1 of the user port and 9V AC at pins 10 and 11.
The tape drive's motor doesn't get power when trying PLAY/FF/REW while the board is powered on with the black screen.
I get a black screen also with a Diag264 ROM installed at U24.
Do you guys happen to have some tips for how to start troubleshooting this board? And is there any chance the TED and the CPU are still good, despite the fact that someone went and installed them backwards?
For the TED, apparently V_dd was connected to DB3, V_ss was connected to A3, and so on. For the CPU, V_cc was connected to P6, V_ss was connected to /RES, and so on. Complete list of pairings below.
** 8360 TED **:
BOARD-----CHIP;
A2------DB0 A1------DB1 A0------DB2 V_dd----DB3 /CS0----DB4 /CS1----DB5 R/W-----DB6 /IRQ----DB7 MUX-----SND /RAS----BA /CAS----AEC PHI0_CLK_OUT-A15 COLOR---A14 CLK_IN--A13 K0------A12 K1------A11 K2------A10 K3------A9 K4------A8 K5------A7 K6------A6 K7------A5 SYN/LUM-A4 V_ss----A3 DB0-----A2 DB1-----A1 DB2-----A0 DB3-----V_dd DB4-----/CS0 DB5-----/CS1 DB6-----R/W DB7-----/IRQ SND-----MUX BA------/RAS AEC-----/CAS A15-----PHI0_CLK_OUT A14-----COLOR A13-----CLK_IN A12-----K0 A11-----K1 A10-----K2 A9------K3 A8------K4 A7------K5 A6------K6 A5------K7 A4------SYN/LUM A3------V_ss
** 8501 CPU **:
BOARD-----CHIP;
PHI0_IN-A14 RDY-----A15 /IRQ----GATE_IN AEC-----P7 V_cc----P6 A0------P4 A1------P3 A2------P2 A3------P1 A4------P0 A5------D7 A6------D6 A7------D5 A8------D4 A9------D3 A10-----D2 A11-----D1 A12-----D0 A13-----R/W V_ss----/RES A14-----PHI0_IN A15-----RDY GATE_IN-/IRQ P7------AEC P6------V_cc P4------A0 P3------A1 P2------A2 P1------A3 P0------A4 D7------A5 D6------A6 D5------A7 D4------A8 D3------A9 D2------A10 D1------A11 D0------A12 R/W-----A13 /RES----V_ss
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