resoldering memory chip temporerally fixes device

Thread Starter

b1xon

Joined Oct 2, 2020
2
Hello I am tryig to repair a broken guitar fx unit
It was bricked and I programed a memory chip for it (25q32)
I soldered it on and it worked but only for a few minutes then the Ui functionallity started to decay slowly until it was completely dead
by resoldering the chip most of the times it works but only for a few minutes.
If I resolder and dont turn it on for an hour then it will work and decay (so time from soldering does not matter)
I checked the chip with thebios writer and it seems ok .
maybe the device is malfunctioning somewhere else but I really dont understaund why reheating the solder joints on the 8 pin bios memorys chip would cause it to temporely fix
could this be a bad capacitor?
I am not an electrisian so I dont have expiriance with repairing espesialy smd

I can not provide a schematic of the unit , it is not publikly available its main component is a ti dsp.

sorry for any bad spelling.
 

ci139

Joined Jul 11, 2016
1,696
? shure that you need to re-solder it and it's not the temperature or "the time operated/ON/lapsed" issue
 

djsfantasi

Joined Apr 11, 2010
6,947
? shure that you need to re-solder it and it's not the temperature or "the time operated/ON/lapsed" issue
Temperature rise based on time operated used to be a problem in 70s era computer mainframes. The memory timing back then was tuned by a drop of solder on long, parallel PCB traces. My DECsystem 20 used to halt after running for an hour. Turns out there was a crack on one of the traces. That particular trace selected an external clock source. Which didn’t exist when the trace opened.
 

Thread Starter

b1xon

Joined Oct 2, 2020
2
It also works for a few seconds if you leave it for a while
but then if you remove powere it dosen't turn back on unles you leave it for a while

the voltage regulator is giving 3.2 volts but my multimeter is not to be trusted ,old and kind of broken
capasitors the big ones seem to be charging when I put the multimeter on them

any Ideas of what I should look for?
 

scorbin1

Joined Dec 24, 2019
44
capasitors the big ones seem to be charging when I put the multimeter on them
If you set the multimeter to resistance, it will charge a capacitor. That's actually how we used to evaluate(less than ideally mind you) capacitors for basic function. Hook an analog multimeter set to resistance across a cap. The meter should spike and then slowly drop back to infinite as it charges.
 

narkeleptk

Joined Mar 11, 2019
474
I've no idea what these circuits look like or whats in them but It kind of sounds like a capacitor problem to me. Maybe one on the vcc side for eeprom.
 
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