speaker protection relay issue

[g1]

And in addition to C314 which Enzo just mentioned, he had previously suggested replacing C315 thru C318. Did you replace them? He suggested them due to previous experience with the same fault in the same model amp. So if one of them turns out to be the culprit after more days/pages of posts, I wouldn't expect much mercy .

[daz]

So pin 1 is -8v. Scope it, or flip your meter to AC volts. Is it clean -8v or is there ripple there? C314 and D309 form a small power supply just for that. A bad cap leaves ripple, which could put the circuit on edge.

I was wondering about D309 after that thing i mentioned i read elsewhere. wonder if i should replace it even tho it reads ok in circuit.
What do i look for on pin 1 on the A/C setting? Fluctuation?

And in addition to C314 which Enzo just mentioned, he had previously suggested replacing C315 thru C318. Did you replace them? He suggested them due to previous experience with the same fault in the same model amp. So if one of them turns out to be the culprit after more days/pages of posts, I wouldn't expect much mercy .

Yes. As i said in an earlier post, i replaced every single electro on the power board. That was the first thing i did.

[Enzo]

AC voltage. I am looking for ripple. It would be 60Hz, so you won;t see meter motion. It is just a thought.

[daz]

AC voltage. I am looking for ripple. It would be 60Hz, so you won;t see meter motion. It is just a thought.

I see. I'll check, tho i'm off on a trip for the weekend for it'll be a couple days before i get to check it.

[g1]

As i said in an earlier post, i replaced every single electro on the power board. That was the first thing i did.

Sorry, I didn't catch that before.
As mentioned above, pin 1 is getting negative voltage from the D309 rectifier. It should be balanced out by the positive voltage through the divider. The divider consists of resistors R337,R338,R339, and R340. Make sure they are all ok.

[daz]

Pin 8 shows only .15v.
The resistors g-one mentioned i will have to check a bit later and post back.

[Jazz P Bass]

Pin 8 shows only .15v.

When does pin 8 measure 0.15V?
At relay drop out?
Previous post indicated it measured 1.5V when the circuit was functioning.
Pin 8 turns the relay on at startup & keeps it on.
Pins 1,2,3 & 7 can turn the relay off.
R337 (22K) & R343 (62K) are pin 8's voltage source.
C316 is the startup timing capacitor.
You have to verify that these three components are good, that the soldering is sound & that the connections are true.

[daz]

When does pin 8 measure 0.15V?

Sorry....I was responding to Enzo's request to see if there was any A/C in pin 1, not 8. Writing pin 8 was a typo. So pin 1 has .15VAC on it.

g-one, R337,R338,R339, and R340 are all reading thier proper valuue even in circuit so i'm sure they're good. (assuming they don't change with voltage)

[daz]

I'm going to try replacing the TA7317. I see many on ebay cheap but they say TA7317P. Does the P have any significance or is it the same IC?

[g1]

In this case the "P" seems to be the only version of the chip so it is the right one. For IC's in general, the P suffix usually denotes a plastic package.

[daz]

In this case the "P" seems to be the only version of the chip so it is the right one. For IC's in general, the P suffix usually denotes a plastic package.

I figured it was something like that. So many have a letter at the end that seems to never have anything to do with the circuit. Thanks.