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Post by Vibroluxer on Mar 20, 2020 14:37:20 GMT -5
I have a Laney VC30. I was playing it the other week and it faded in and out, just once, then it seemed ok. I chalked it up to a bad cable from the guitar to the amp. Then a week later it faded out never to return. It Powers up but no sound. No hum, no static, zip.
It's supposedly a new amp and I got it on reverb. The seller offered to pay for the repairs but the only tech he knows works only with speakers.
I'll happily ship the chassis, I just don't know to whom.
Any suggestions?
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Post by jazzguy on Mar 20, 2020 14:52:53 GMT -5
You might try asking Willie.
I believe he's retired but probably knows someone.
Or you could try Yelp in your area and read the reviews.
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Post by Peegoo 🏁 on Mar 20, 2020 15:11:56 GMT -5
Try the following, in order, and report back:
1. Check the rear panel for fuses. Some have a single fuse for AC mains in, and the amp won't power up if it is blown. Some also have a 2nd fuse. If this one is blown and the AC mains fuse is not, the amp will power up and make no sound.
2. Tap the speaker's terminals with the contacts of a 9v battery. If the speaker makes a THUMP sound, the speaker is good. Unplug the speaker's cable from the jack on the rear of the chassis, and do the same battery tap test on the plug. If it goes THUMP, the cable is good. Do not hold the battery in contact beyond a tap. Several seconds can cook a speaker, but a tap is harmless.
3. Gently remove each tube and stick it back in. This scrubs the tubes' contacts in the sockets and can reestablish a poor connection due to oxidation on the metal contacts.
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Post by Peegoo 🏁 on Mar 20, 2020 15:31:06 GMT -5
I looked up the schematic, and the VC30 does have the secondary fuse HT fuse (315mA), but it's in the chassis, on the ground side of the solid-state rectifier. There's also a 630mA fuse on the rectifier that feeds the standby switch, but I suspect it's the 315mA fuse because that one is the weak link of the pair. Chances are good this is the blown item, if the speaker and tubes all check out. I'm assuming the tubes' heaters are all working (dull orange glow in the center means they are working). **I am not an expert on this stuff** like the amp gurus we all know here, but I can read a schematic and offer some suggestions. Look here:  |
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Post by Vibroluxer on Mar 20, 2020 15:54:15 GMT -5
Thanks to you both! Time to get out my toolbox. I'll report back soon.
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Post by Peegoo 🏁 on Mar 20, 2020 16:06:46 GMT -5
I did some further reading on this amp.
Laney recognized an issue with the low-current rating of that 315mA HT fuse (it was a common cause of failure), so on subsequent models they changed it to 500mA. I saw this on a few later schematics.
If that fuse is the culprit, don't do a like-for-like replacement; stick a 500mA rated fuse in there.
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Post by Stratluvr on Mar 21, 2020 18:43:43 GMT -5
Make sure you read up on how to release any electricity that may be in the caps first.
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Post by Peegoo 🏁 on Mar 21, 2020 20:22:18 GMT -5
Yeah, because it you don't do it on purpose, you might do it unintentionally. Which could be fatal.
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Post by Vibroluxer on Mar 22, 2020 15:37:29 GMT -5
Thanks for the advice. That's the one thing I know about amps! But it never ever hurts to be reminded.
I'm hoping to get to this today and I'll let ya know.
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on Mar 23, 2020 6:07:23 GMT -5
...it faded in and out, just once, then it seemed ok... Then a week later it faded out never to return. It Powers up but no sound. No hum, no static, zip... Was it a slow clean fade out, ie rather than a spluttery, fizzling out type of thing? If so, that indicates a bad connection in the heater circuit. So definitely check - carefully - for each tube getting hot. If you put your ear right on the speaker, is there no hiss/hum background noise at all when the amp is powered up and (apparently) ready to operate? If there is a little noise, try a link cable between fx send and return jacks. If you get stuck, there's got to be someone with the necessary tech skills in the Pennsylvania region, surely? It's not a super complex amp. www.thetubestore.com/lib/thetubestore/schematics/Laney/Laney-VC30-Schematic.pdf |
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Post by Peegoo 🏁 on Mar 23, 2020 15:34:21 GMT -5
"If there is a little noise, try a link cable between fx send and return jacks."
Great advice! Years ago I had an amp come in (Ampeg VT120) that lit up with nothing coming out of the speaker. I tried the cable between the loop jacks, and BAM, all was working. I cleaned the two switching jacks and that fixed the issue.
Some jacks you cannot get into to scrub the contacts, but flooding them with contact cleaner and doing "the ol' in-out" with a plug, followed by blowing them out with compressed air, will often fix the enclosed jacks.
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Post by Vibroluxer on Mar 23, 2020 21:09:19 GMT -5
Well, I did the battery test and it's not the speakers. All the tubes have a nice steady glow so now I have to take it apart. Sure wish it had the metal straps like Fenders.
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