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Topic: Reverb quit - ideas Follow Up - FIXED |
Keith Bolog
From:
Wisconsin, USA
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Posted 12 Feb 2019 6:04 am |
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The reverb quit working on my Milkman. I dont remember any particular shock or bump it took.
Examining the tank, there doesnt seem to be any missing loose or damaged springs, or loose wires. Furthermore, you can produce the 'crash' sound by upsetting the amp. But it is a rather vibrato-ey. Trying an old tank from a Peavey into the RCA coinnections produced a very slight amount of reverb with the knobs cranked.
I also replaced the reverb circuit tube to no avail.
Before I take the amp to a tech, can anyone tell me if the tank can still 'go bad' somehow?
_________________
Say what you mean. Mean what you say.
Last edited by Keith Bolog on 25 Feb 2019 7:12 am; edited 2 times in total |
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Richard Sinkler
From:
aka: Rusty Strings -- Missoula, Montana
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Posted 12 Feb 2019 6:28 am
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Get ahold of Tim Marcus, the builder of the amp.
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Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, NV400, NV112 . Playing for 54 years and still counting. |
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Michael Brebes
From:
Northridge CA
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Posted 12 Feb 2019 8:20 am
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If you have the crash by upsetting the amp, then it is either the drive circuit, which in most Fender-style amps uses a 12AT7, a bad cable between the drive and pan, or it is a bad input coil on the reverb pan.
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Michael Brebes
Instrument/amp/ pickup repair
MSA D10 Classic/Rickenbacher B6/
Dickerson MOTS/Dobro D32 Hawaiian/
Goldtone Paul Beard Reso
Mesa Boogie Studio Pre/Hafler 3000
RP1/MPX100 |
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Jerry Erickson
From:
Atlanta,IL 61723
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Posted 12 Feb 2019 12:10 pm
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The Peavey tank won't work well with the Milkman amp as the Peavey tank is designed to work in a different type of circuit.
If you take the reverb tank out of the amp and look at the input side, you'll probably find a broken wire at the connector or the inductor. |
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Patrick Ickes
From:
Upper Lake, CA USA
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Posted 12 Feb 2019 6:39 pm Don't call Tim
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This has been addressed here before. It's 99% of the time the reverb tank failed. Swap tubes, then if still bad, buy a replacement tank, they're cheap, $20 or so. Get the correct ohm load rating. There should be a part number on the tank, I think it's a MOD tank Tim uses.
Patrick |
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Tim Marcus
From:
San Francisco, CA
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Posted 12 Feb 2019 7:19 pm
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I posted a troubleshooting guide a while ago in this thread:
https://bb.steelguitarforum.com/viewtopic.php?t=318082&sid=8edc99e9db4e0022039d30a7e6df7dc5
99% of the time reverb goes away because of an issue that is external to the amplifier. Since this post is going to live on the forum forever - here is a troubleshooting and parts list for all Milkman amplifiers, and it will double for Fender and just about any tube amplifier with reverb.
The reverb circuit consists of 4 external parts in this order:
Reverb driver. This is typically a 12AT7 preamp tube, and its the middle tube in your Half and Half. You can replace this tube by simply pulling it out and putting a new one in.
https://www.tubesandmore.com/products/12at7-ruby
from there, the signal goes through an RCA cable:
https://www.tubesandmore.com/products/cable-rca-right-angle-plugs
to a spring reverb tank:
https://www.tubesandmore.com/products/reverb-tank-mod-4ab3c1b
and back up into the amp where it meets the recovery tube usually a 12AX7:
https://www.tubesandmore.com/products/12ax7a-c5-ruby-tubes
and thats it. Usually replacing one or all of those small items makes it come back to life.
Some of the older Half and Half amplifiers have a 1/4" TRS to RCA cable. If you want to replace that, you will need to contact me for a replacement because those were custom built. Or if you have soldering chops, you can probably just re-terminate the connectors (where the cable is most vulnerable to failure)
If after replacing all external components your reverb is still not working, you can send the amplifier chassis in for repair. Out of all the repair emails that have come through over the years, that has only been the case 1 time. Most of the time I just send parts or suggest customers replace tubes and thats all it takes.
Changing tubes and reverb tanks is similar to replacing a tire on a car. Its not fun, but its relatively easy |
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Keith Bolog
From:
Wisconsin, USA
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Posted 13 Feb 2019 9:40 am Thank you Tim
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Thank you everyone especially to Tim, Who has ALWAYS answered my phone calls in the past politely, patiently, and thoroughly.
I posted here first because I thought this was a simple fix others have had, didnt want to bother Tim with ignorant minutiae, rather, save his counsel for a REAL problem.
I am assuming there is something wrong with the tank which I cannot see, and was going to try another tank next. If that isnt the problem, I will have a spare for its inevitable failure.
Cheers
_________________
Say what you mean. Mean what you say. |
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Patrick Ickes
From:
Upper Lake, CA USA
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Posted 13 Feb 2019 1:05 pm
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Be sure to let us know what the fix is.
Patrick |
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Keith Bolog
From:
Wisconsin, USA
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Posted 18 Feb 2019 9:26 am
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Found small disconnected solder joint in the reverb tank. Amp sounds good now.
Thanks.
_________________
Say what you mean. Mean what you say. |
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