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post #1 of 5 Old 02-28-2013, 05:24 PM - Thread Starter
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Thought i'd share my experience.

Symptom: random unpredictable audio flickering, then dropouts, then channel cuts off. A turn on the power button, or a restart cures it.

Cause: bad VS-24MB-NR relay, $2.65 at Mousser.

Joe at Sherbourn confirms that at about 10 years these relays fail, testimony to it, i now have 4 out of 5 channels on one of my 2 5/1500As doing it. He strongly advised replacing all relays.

Repair tools:

1. VS-24MB-NR relays.
2. Philips screwdriver, power for removal only.
3. Forceps, very useful for pulling connectors.
4. Pen and paper, you will need to draw a diagram
of the wiring you remove, the back of each board has
seven position connectors.
5. Solder gun, an air rework tool is a blessing, the X-Tronic
6040 station is a Godsent. Desolderging wick to pull extra
solder after old relays removed. Rosin core solder.

The relays are under the two large capacitors behind the

Sequence (leave the front and transformers alone):

1. Lay amp on back feet, remove all bottom plate screws, the
modules are now only attached at back. You will have to remove
bottom right foot looking from bottom.
2. Lay it down, remove top plate.
3. Remove back screws holding XLR and RCAs.
4. Remove all connectors, make a map with positions. Not too many, really.
5. Pull gently transformer end of board upward then back until
you remove it completely, always slowing down to remove wires
you may have hooked up. There is room to wiggle as the boards
come lose.
6. Take rework air gun with 2.5mm blower, or soldering tip and heat
over the wick, the old relay will drop out.
7. Put new one in, clamp it to board, solder. Heat the pins, do not melt
solder on gun, nice perfect Hershey kiss droplet identical to factory ones
is a sign of a good contact. Don't worry, if a dumb PCP internist can do it,
you can do it:)

I am now sitting in front of my Signature S8 mismatched (v.1,2,3) system auditioning Warner Japan's release of the Eagles, Hotel California in 5.1 is xxxxing amazing, really. Gone are the dropouts, 3 days now.
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post #2 of 5 Old 12-26-2013, 04:37 PM
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Thanks very much for sharing this as I have this same amp and figure it should start happening soon. However it sounds a bit tricky, I wish there were some pictures to go with it. I don't even know what an air rework tool is. Once I fixed my Mitsubishi WS-65813 HDTV by replacing the capacitors so I still have a soldering gun from that. But this sounds much more complicated...

Panasonic 60VT60
Sherwood P-965
Parasound 2X205
Sherbourn 5X200
Polk LSi9's

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post #3 of 5 Old 08-07-2014, 12:56 PM - Thread Starter
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FYI amps running strong. Bryston 9BSST upgraditis resisted, I believe my next amp will be an additional balanced 2-channel behemoth, dedicated to the XLR stereo off the UD9004 via the CP700.
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post #4 of 5 Old 11-07-2014, 07:04 PM
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Caps bad

It seems the caps on mine have gone bad. Any chance you have a part number for those?
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post #5 of 5 Old Today, 03:42 AM
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Update - I just replaced the five speaker relays on my 5/1500a and the original VS-24MB-NR has been discontinued.

The replacement part number is NTE R22-1D16-24 or Fujitsu VS-24STCU-E. The Fujitsu parts are form C so you need to clip off the NC contact pin. Mouser has the Fujitsu parts, and they are marked TAKAMISAWA which is the same manufacturer as the originals.

Also, the VS-24MB-NR relays can be cleaned! The tops pop off, exposing the contacts, which can then be cleaned and burnished. So you don't need to buy new relays if you are comfortable with cleaning relay contacts. I figured this out after I ordered the relays, so I went ahead and replaced them.

Last edited by Tom Rosback; Today at 05:58 AM.
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