97s I/O Pod

[teenix]

(05-28-2020 09:04 PM)[kby] Wrote:  Hi Tony,

Time to order a full set since Katie’s recommendation is to narrow the board and then replace while testing each chip. I don’t have a replacement working board so,have to forgo the first step, unfortunately. Also I (1) don’t have a chip tester and (2) since the risky part is soldering and desoldering which has to be done whether or not I can determine that a specific chip is bad, I figure I’ll just plan on replacing them all, hope I don’t get any DOA chips or cause any infant mortality, and only resort to buying a tester if brute force fails. I did buy a nice desoldering gun primarily for this project, which helps.

I wanted to make sure I decided your handwriting, though. Are all the chips on the third sheet (page 2) 4014, or are some 4016? No insult intended; I have PhD handwriting, which is worse.

If you haven't done it already, I'd still try looking for a warm or hot chip (or component) after the board has been powered for awhile first. It might indicate where the problem lies.

Most look like 4000 series ICs which are still available. One is a 74C174, but 74HC174 is available.

There is an unmarked chip on Control PCB (5), but you should be able to find it on the board.

Yes, they all look like 4014 except for one 4035.

The new chips are reasonably rugged, but these are static sensitive so care will be required while handling. Solder the power pins first (Usually GND - 7 or 8, and VCC - 14 or 16).

One big problem is that there are a couple of HP chips in the circuit.

Control PCB (2) 1818-0965 (not sure about the 9) but I haven't seen a reference to any 1818-0x65 chips, or the 1818-0496 on Data PCB (4). If one or both of these are fried, then (yikes).

These drawings are from the amazing efforts of Tony Duell.

Good luck.

cheers

Tony