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Author Topic: Peavy Rage 158 no sound after 1-5 mins (SOLVED)  (Read 2004 times)

g1

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #15 on: June 16, 2019, 04:29:48 PM »
Schematic shows pin3 connected to ground, so no insulation needed for the IC.
Check D10 in circuit with your meter.  Check for any solder bridges at the IC pins.

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #16 on: June 17, 2019, 09:06:00 AM »
Schematic shows pin3 connected to ground, so no insulation needed for the IC.
Check D10 in circuit with your meter.  Check for any solder bridges at the IC pins.

D10 and D9 I get a beep both polarities with the diode test on my meter. I pulled them out before and they tested fine out of circuit.

g1

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #17 on: June 17, 2019, 12:09:52 PM »
Check with meter set to ohms, lowest range.  Across D10, with it in circuit.

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #18 on: June 17, 2019, 01:09:18 PM »
Check with meter set to ohms, lowest range.  Across D10, with it in circuit.

Seems to be all over the place. Either climbing to around 250k Ohms one polarity, other polarity drops from from 1m Ohm. But I also get all sorts of other readings across it.

g1

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #19 on: June 19, 2019, 04:24:53 PM »
Can you check same with the board fully mounted?

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #20 on: June 19, 2019, 10:40:09 PM »
Can you check same with the board fully mounted?

Basically the same, once side climbs up to 260k, the other climbs down from 1.2m until about 300k then drops to 0 and starts climbing up.

g1

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #21 on: June 20, 2019, 12:10:20 AM »
How about checking resistance from heatsink to each of the IC pins.  The only one that should be low resistance is pin 3.

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #22 on: June 20, 2019, 07:34:40 AM »
How about checking resistance from heatsink to each of the IC pins.  The only one that should be low resistance is pin 3.

Pin 3 is a dead short, as expected. The other pins are 250k or over 1m.

g1

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #23 on: June 20, 2019, 01:46:19 PM »
How about resistance of R44 to ground?  (try both sides)

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #24 on: June 20, 2019, 02:27:34 PM »
How about resistance of R44 to ground?  (try both sides)

2.5m on both sides. Resistor reads proper at 4.7r across.
« Last Edit: June 20, 2019, 04:58:05 PM by substatica »

psafloyd

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #25 on: July 04, 2019, 02:10:56 PM »
There are at least two editions of the 158 Rage. The later/latest one had a switch to switch between modern and vintage voicings. If your one has this and the schematic doesn't, it could be more than the switch got altered.
   

Q: Next time it kills the sound, leave it running, ball up your fist, and whack the top of the amp.  Does the amp come back on, even for a moment?
A: No.

Q: Does the amp react to your whack in ANY way, like a noise?
A: No.

Q: When it dies, listen CLOSELY to the speaker, is there any background hum or hiss? 
A: Yes.

Q: Turn up the controls to hear that better potentially.   If there is any such background, to the volume and tone controls affect it at all?
A: Low hum, not affected by volume or tone, buzzes louder if I short the signal cable with my thumb.

Q: Get the schematic from customer service at Peavey, and then see if your power supplies are remaining up or if they are going out.
A: 120VA into the transformer, 25VA out  in the no-signal state.

Q: With it running and signal applied, poke each part on the board with a wooden chopstick or similar.
A: No effect.

I tested the diodes, they all read good except for the two 1N4003's by the power transistor, they short both ways -- maybe that's expected? It also seems if I leave it on in the no-signal state for 5 minutes or so the power cycle no longer fixes the issue, I'll have to wait and see if it works again after being off for a while. That brings me back to heat, but nothing on the board seems overly hot (hit it with infrared thermometer).

Also, still trying to determine if that's the correct schematic. It's a Peavy Rage 158 w/ Transtube, but the component markings aren't all matching up. The initial sold solder I fixed was on an R49 which I can't seem to locate.

The amp is the same as the one pictured on this thread,

https://www.diystompboxes.com/smfforum/index.php?topic=97068.0

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #26 on: July 04, 2019, 04:27:24 PM »
There are at least two editions of the 158 Rage. The later/latest one had a switch to switch between modern and vintage voicings. If your one has this and the schematic doesn't, it could be more than the switch got altered.

Mine does have this switch, but the schematic seems pretty bang-on, I'll have to look closely for differences.

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #27 on: August 04, 2019, 12:55:17 PM »
I replaced C26 which is listed as 100nf, but the actual component was 200nf.

The board can ground to the chassis and everything works -- however if the ground of the input jack is connected to the chassis (as it is when assembled as a plate on the jack tightens against the chassis) the signal drops out.

Thoughts? Summarizes as the signal lost when input ground connects to chassis.
« Last Edit: August 04, 2019, 01:43:04 PM by substatica »

phatt

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #28 on: August 05, 2019, 06:22:49 AM »
Best I can make out is that you have 2 Grounds/Commons.
AGND1 & AGND.
AGND1 is likely Com for chassis as well as power amp but after that the ground is lifted by R63 (47R).
So AGND is separated from ANGD1 by R63.
I can only assume that grounding the input socket upsets the bias of the whole preamp. Better minds may know more?

The schematic shows the input com tag is actually grounded to Chassis so it makes no sense as drawn. xP

The drawing also shows the input socket (J1) is a switching socket but your picture shows a non switching socket.
I can only assume it has been replaced at some point,, possibly you need a switching socket.
sorry i can't be more help.
Phil.

substatica

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Re: Peavy Rage 158 no sound after 1-5 mins
« Reply #29 on: August 05, 2019, 08:17:51 AM »
The picture is a switching socket, inserting the 1/4" plug lifts the contacts opening the switches.

Upsetting the bias sounds like it may be the case because the max volume seems to fluctuate if the ground contact is intermittent.

 

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