Peavey VTX Classic schematic and transistor M 5884

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mrawls24
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Peavey VTX Classic schematic and transistor M 5884

Post by mrawls24 » Sun Nov 09, 2008 9:21 pm

I have a Peavey VTX Classic from the early 1980s. The amp stopped putting out sound and one of the 6l6gc tubes started glowing red. After some component testing one of the M 5884 marked transistors checked bad. I have not been able to find a listing for this Motorola transistor on the Internet. I tried a replacement audio output transistor I found in a cross reference database (MJE15030). The new transistor stopped the tube from glowing red, but the audio is a little fuzzy now even in the clean channel. It looks like I may need to find an M 5884. Does Peavey stock those or is a there a more suitable replacement transistor? I checked the 6l6gc tubes in a tube checker and they tested good with no leaks or shorts.

Is the schematic available on Peavey's website for the Peavey VTX Classic? The circuit boards reads "81 Classic".

Thanks,

Michael

mrawls24
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by mrawls24 » Mon Nov 10, 2008 6:06 pm

I fixed my amp! The Peavey repair guys emailed me a schematic, and recommended I also replace the two MPS6530 driver transistors. One of them did check bad. The MPS6530 cross referenced to a 2n3904 transistor which is available at Radio Shack. After a trip to Radio Shack I replaced the two driver transistors and now my amp sounds like it's old self again.

As it turns out the MJE15030 is the correct cross reference for the older M 5884 transistor. I had partially fixed the amp when I replaced both M 5884 transistors with two new MJE15030 transistors. I just needed to also replace the two driver transistors (MPS6530/2n3904).

Thanks again Peavey!

Michael Rawls

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Enzo
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by Enzo » Tue Nov 11, 2008 5:42 am

SInce it works, probably OK, but you might check the two 5.6 ohm 5w power resistors just left of the two 15030 transistors. And since the small limiting transistors failed, you might want to verify for value the little resistors around them, the 47 ohm and 120 ohm ones.

Those two power resistors are where to take the voltage readings mentioned in the schematic notes for proper bias levels.

Are the power tubes now fresh ones?

mrawls24
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by mrawls24 » Tue Nov 11, 2008 4:41 pm

Enzo wrote:SInce it works, probably OK, but you might check the two 5.6 ohm 5w power resistors just left of the two 15030 transistors. And since the small limiting transistors failed, you might want to verify for value the little resistors around them, the 47 ohm and 120 ohm ones.

Those two power resistors are where to take the voltage readings mentioned in the schematic notes for proper bias levels.

Are the power tubes now fresh ones?
I checked the voltages specified on the schematic diagram, and they are within specified limits.

The tubes are the same ones I have been using, but they easily check good on my tube tester with no shorts or grid leakage.

bassetrox
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by bassetrox » Mon Feb 25, 2013 12:43 pm

Hi, would you be willing to share that schematic please? the only one I've found is unreadable.

Thanks,

R

mrawls24
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by mrawls24 » Mon Feb 25, 2013 2:50 pm

bassetrox wrote:Hi, would you be willing to share that schematic please? the only one I've found is unreadable.

Thanks,

R
Here it is. Peavey VTX Classic schematic.

http://www.shadowstorm.com/cb/schematic ... lassic.pdf

Michael

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Enzo
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by Enzo » Mon Feb 25, 2013 4:29 pm

And you can always get any Peavey schematics you want by contacting customer service at the factory.

EL SkyNerd
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Re: Peavey VTX Classic schematic and transistor M 5884

Post by EL SkyNerd » Wed Mar 29, 2017 7:52 pm

Hi all to you all, Because of this post I was able to fix my Peavey "Flight Case MX" Amp This is the first time I have ever repaired anything that is Solid State. I had no clue where to look. I been watching youtubes about transistors, capacitors, tubes, magnets cathodes soldering and op amps. Still didn't have a clue what was wrong with my amp. I do believe history repeats itself on a production line. Hey It worked out okay this time. Now the fun part . Its going to take at least an hour,putting ( I mean building ) the Flight Case back together again . Thats why I bought this amp Its stronger than tank

Oh yeah I got the transistors from radio shack 70% off It is sad to see them going out of business.

Thank you for posting this post

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