1980 Fender Super Reverb repair

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M Fowler
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1980 Fender Super Reverb repair

Post by M Fowler » Sun Oct 22, 2017 1:58 am

Been working on repair this 1980 MV Super Reverb.

Some one has been playing around in this chassis something terrible.

Tube match pot was wrecked and miss wired. Replaced with 10kL bias pot no tube match.
Filament balance pot broken, ordered new 100R pot and will replace tomorrow.
Broken 1MA push/pull MV pot I just happened to have one in my stock.
Replaced OT with new 4/8R secondary so owner can run new baffle board with 2-12".

Found the ground wire for the full wave bridge rectifier was missing?
Rewired the amp back to MV with boost.

It was a Fricking mess, but I clean her up. This might be a good candidate for Hotel Hog or Phoenix.
1980 super reverb repair 1.jpg
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Firestorm
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Re: 1980 Fender Super Reverb repair

Post by Firestorm » Sun Oct 22, 2017 8:35 pm

70W "ultralinear"?

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M Fowler
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Re: 1980 Fender Super Reverb repair

Post by M Fowler » Sun Oct 22, 2017 9:34 pm

No it is not ultralinear.

Firestorm
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Re: 1980 Fender Super Reverb repair

Post by Firestorm » Mon Oct 23, 2017 1:25 am

I saw the 10W resistor and assumed.

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M Fowler
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Re: 1980 Fender Super Reverb repair

Post by M Fowler » Mon Oct 23, 2017 10:51 am

That 10w resistor knocks the voltage down for reverb transformer.

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M Fowler
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Re: 1980 Fender Super Reverb repair

Post by M Fowler » Mon Oct 23, 2017 10:15 pm

Replaced the broken 100R filament balance pot.

Changed reverb channel slope resistor from 100k to 150k and treble cap from 250pf to 1000pf.

The amp rocks, the owner sounded great through it and his smile was indicating success so it went home with him.

Not my favorite Fender amp to work on.

Mark

Stevem
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Re: 1980 Fender Super Reverb repair

Post by Stevem » Tue Oct 24, 2017 11:02 am

Work on, why they are all so similar?
Most times with good Amps just like it is with sex, it's best to just plug straight in!

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M Fowler
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Re: 1980 Fender Super Reverb repair

Post by M Fowler » Tue Oct 24, 2017 12:22 pm

Nothing similar about this Fender compares to the early BF and SF amps I've worked on.

The bridged rectifier is different, the output tube match circuit is funky to me, biasing is different to me,
the wiring is so long and unorganized, the master volume is different and the boost switching.

It is the first time I have worked on such an animal so that is why I said what I said.

Mark

pdf64
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Re: 1980 Fender Super Reverb repair

Post by pdf64 » Tue Oct 24, 2017 2:16 pm

I thought that only the 70W DL SR had the FWB rectifier board (500V HT); previous versions having a tube FW rectifier, choke and 445V HT?
Did it have a choke originally?
What's the PT part #, eg 022798, 013895?
Note that the original speakers in the 70W were 16ohms, and that the original OT used a 4 ohm output (green) with a 2 ohm tap switched in when the ext speaker jack was engaged http://schems.com/schematicheaven.net/m ... tr_rev.pdf
Last edited by pdf64 on Tue Oct 24, 2017 4:48 pm, edited 1 time in total.

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sonicmojo
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Re: 1980 Fender Super Reverb repair

Post by sonicmojo » Tue Oct 24, 2017 3:23 pm

Yep, I hate servicing those later spaghetti amps.....but have you ever seen the inside of the short-lived 90s Fender ToneMaster? Run away!
---------
Bryan

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M Fowler
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Re: 1980 Fender Super Reverb repair

Post by M Fowler » Tue Oct 24, 2017 8:52 pm

That's the schematic I used but this was not a stock amp it had been hacked up over the years by the Butcher of Luverne.

I replaced the replaced OT with a 4&8 ohm transformer Heyboer.

The old OT was not UL either. They hacked the bias/tube match as well as other parts.
The MV was broken removed from circuit. Wires jumpered and parts removed from board.

Apparently this amp had been in storage for many years before my friend got it and asked me to sort it out.
The front of the chassis was pushed back towards the rear of the amp. Modified a squeeze clamp to push rather then pull to straighten it out.
The cab was apparently not beaten up like the chassis was?

I studied schematics and photos to put this thing back together and then I tested for tasty playing ability.

Mark

pdf64
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Re: 1980 Fender Super Reverb repair

Post by pdf64 » Wed Oct 25, 2017 8:23 am

Good stuff, bent chassis can be a pain to sort out but it's nice to tidy up a mess and send the owner off smiling8)

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rooster
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Re: 1980 Fender Super Reverb repair

Post by rooster » Tue Nov 07, 2017 7:41 am

I just repaired a '79 like this, although slightly different inside. No transformer choke, not UL, and, surprisingly, the 4 10" speakers were 16 ohms @ wired for 4 ohms. The OT tranny seemed bigger than a SFB (which would have been 4 ohms) but I could have been wrong. Had about 500 VDC on the plates,
Most people stall-out when fixing a mistake that they have made. Why?

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