Reddish 500 EQ

[ruffrecords]

Would you happen to have a moment for zoom. I believe this would save ALOT of time and troubleshooting can be real time. In other news. I believe C29 is about to pop.. Not sure what the hell is going on but this is getting Crazy.

In all probability it will turn out to be something really simple. Subtle faults are extremely rare.

Cheers

Ian

 

[capacitorless]

I believe C29 is about to pop..

If you give your reasoning on these types of things, that will make the process go more smoothly. Details matter So, why? Without knowing the symptoms we are left to guess.

Is it possible the 500 rack is putting out higher voltages than nominal, or voltage in an unexpected place? I'm guessing not because the other card is working correctly and you're getting 24v across the relay. Just fishing here. I'm assuming you swapped slots with the working card to rule out a funky slot, but just making sure.

I'm out for the afternoon but will check back in this evening. Like Ian said, it's typically something obvious even if we haven't run across it yet.

Please check the relay DPDT pins for voltage as well (see my previous post). If DC is on there, that could cause interesting things to happen.

 

[capacitorless]

Also, if anyone can chime in regarding how the audio and power supply grounds are usually coupled in a 500 rack (maybe it varies), that would help I'm new to 500 rack stuff. I'm specifically wondering if we can always use (eg) the audio ground for voltage measurements, or if we simply use whichever ground is appropriate for the section of the circuit in question.

@Forcemusicgroup I would reiterate that printing out the schematic and writing down the resistance/voltage measurements would be helpful - not just for you but for anyone trying to help you debug this problem. That could be photo'ed and uploaded here for us to look at. It might speed things up greatly.

 

[JMan]

I can try to get on a Zoom call with you, but it wouldn't be until this weekend at the earliest.

Agreed with Ian and capacitorless, once we find the fault we're probably going to kick ourselves for not seeing it right away.

If you're worried about C29, an obvious first check would be to make sure it's oriented correctly.

We're getting lots of variables introduced here, and of course the tricky thing about that is that it can point to the problem or it can divert attention away from where we actually need to look, and it's tough to know which one is happening sometimes.

 

[Forcemusicgroup]

Yep. The cap popped. I pressed down on it and a fluid came out hissing. This will have to be put off until I can get a few more caps