Peavey Series 100 Classic 50W 2x12 No Output

[Helmholtz]

The so-called "snubber" diodes clamp the OT primary voltage to safe levels and thus protect the OT when no load is connected.
You could use two 1N4007s in series per side.

[J M Fahey]

Speaker cable reads 7.7 ohms.

What does this mean?

[misterc57]

Speaker cable reads 7.7 ohms.

What does this mean?

Sorry, that was vague. The combo cab has two speakers wired in parallel and the cable they are wired to reads 7.7 ohms on the DMM, even though the output calls for 4 ohms.

I have not dug into that yet, perhaps the cable has some resistance.

Thank you

[misterc57]

If this helps give you some ideas, here is how I replaced the caps in the Power Supply section. For the 60uf cap, I had two 30uf caps - so I put them in parallel.

How do you like the Mod filter caps?

[TomCarlos]

How do you like the Mod filter caps?

Ask me in 10 years!!

I follow a handful of Tech on YouTube and they have used these caps. Keep in mind, (to me) this amp is not considered high end. So I am not about to drop money on the most expensive caps, tubes, etc. So far, one year into the repair I did, my friend reports no issues.

By placing the caps side by side, and the resistors as I did, it made it easier to look at the schematic and make the connections and take measurements against the schematic.

[TomCarlos]

The combo cab has two speakers wired in parallel and the cable they are wired to reads 7.7 ohms on the DMM, even though the output calls for 4 ohms.

Start by checking your meter (alone) first. When you touch the test leads to one another, what is the resistance reading? It might measure something like .3 (point three) ohms or slightly more. Get a starting point by making sure you do not have an issue with your meter or test leads.

Do the speakers have any markings on them? Please take a photo of the speakers if you can.

Do the speakers wires have connectors or do you have solder connections on the speakers?

I would disconnect one end of a cable that goes to each speaker and measure the resistance right on each speaker (with nothing connected to it). If these are stock speakers, each one would measure something just under 8 ohms (dc resistance).

Check the cable and wires end to end. Make sure you do not have an open.

I am questioning your output transformer. Take a look at the photo of the amp that I worked on. Do you see anything that is different? Someone (either yours or mine) has been installed 90 degrees out of alignment (orientation). Go online and look for images of the same amp. You will see photos that match the one I posted here. See if you have a part number on the output transformer. It should read DF-184 (or maybe read 70500184). According to Enzo in the post 1970's 50 watt Peavey Classic, there could be two taps, 4 and 8 ohms). So who knows, maybe someone made a mod to your amp.

[g1]

I would disconnect one end of a cable that goes to each speaker and measure the resistance right on each speaker (with nothing connected to it). If these are stock speakers, each one would measure something just under 8 ohms (dc resistance).

Check the cable and wires end to end. Make sure you do not have an open.

Yes. Two 8 ohm speakers in parallel reading 8 ohms, I usually assume one is blown.