QUAD 66 Pre Amplifier Anyone Worked On Before ?

[ReeceyBurger123]

Hey everyone, no images just yet of the device. Wanted to ask if anyone has experience with this preamp ? It's intermittent something by the the main IC or the IC itself is faulty. IC 302 on the schematic, if you freeze near this area the amp works. So far I've done the following:

Soldered cpu to board-removed 40 pin socket
Replaced 4mhz clock
Replaced all caps
Cpu has clean 5v
Caps near cpu are ok
Resistors and resistor pack test ok
All other voltages are there and working

Two small ZTX750 transistors near by I have on order, they test ok on the meters and have 6.8v on each stable, I'm trying them anyway.

Anything is appreciated, here's the data sheet. Will grab images shortly.

https://cdn.badcaps-static.com/pdfs/...54722fffc3.pdf

[CapLeaker]

Re: QUAD 66 Pre Amplifier Anyone Worked On Before ?

I ran into a Plasma TV about 8 years ago that got struck by lightning and fried the HDMI IC. As soon as that IC got hot the TV shut down (maybe 1 to 6 seconds, depending on how cold the main board was. Long story short, the TV worked as long as I froze the IC with a can of air upside down.

Another example:

Lost audio on an amp. I was able to pinpoint the problem down to an area with a circumference to 1 inch. Resoldered all SMD parts double that area, no go same thing. I reflowed the area with my hotair, problem solved. To date it's still working like a champ. Go figure.

Depending on how big the problem area is, you may have to depopulate, check all traces and via's, repair, clean, then repopulate.

Kinda hard without seeing some pix.

[ReeceyBurger123]

Re: QUAD 66 Pre Amplifier Anyone Worked On Before ?

Cpu Ic was faulty, no fix in the end. Could not get it stable in the end. Thanks CL hope your good

[CapLeaker]

Re: QUAD 66 Pre Amplifier Anyone Worked On Before ?

That’s too bad… yeah, I am still around, just busy as usual at work. Hope you’re good over there as well, buddy!