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Need a service manual for this. I find 'em online... but not gonna pay $25. Both channels protect lights are on. No load connected. Looked internals over and don't 'see' anything.
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DO both channels seem to be getting ALL their power supplies?Education is what you're left with after you have forgotten what you have learned. -
Good question. Not familiar with this amp OR the layout/design. Would like a schem to makes sense of. It. I guess I could probably try to figure that out.Comment
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Yes, of course the book makes life easier, but a power amp will have output devices, whether TO3s or three-leg transistors. ANd of they are NPN and PNP, then you will have split supplies, so look for both V+ and V- on the collectors. If they are all NPN, you have quasi-complementary, like a PV 400BH, and half of them will have V+ on the collectors and half will have V- on the emitters. I doubt that Panasonic unit will be quasi.
And of course low voltage suplies can be found on any op amp IC.Education is what you're left with after you have forgotten what you have learned.Comment
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Okay that's what i would have guessed or assumed. But typically that gets me into trouble. Now that you've told me so I'm more confident in troubleshooting it. Thanks. Any ideas on that PMP4000 thread? Only questionable thing I found w scope was the fan supply. Tempted to replace that voltage regulator and/or 26v zener.Comment
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Okay so high V rails are good. It's not quasi. There are NPN and PNP. Power transistors all have identical voltages which look good. Collectors +/-45v. Bases +/-.6v. Emmiters 0v. There are 3 8-pin dual opamps. 1 of them has +/-15v on pins 4/8. The other two aren't quite right. Pins 4 have -15v but pins 8 on those 2 opamps are at +11v. I searched around for a voltage regulator. Was looking for something like a 7915. Can't find any. So at this point I can't see where the low v supply is. I diode checked all diodes that I could see and didn't find any obviously bad.Comment
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Either of those op amps getting hot?
I would expect three terminal regulators, but they could have made up a discrete reg circuit. Look at the power transformer wires. There would be wires for the main 45v supplies, and probably another winding for low voltage supplies. See if you spot that, and it ought to feed right to the rectifiers, and from there to a regulator circuit.
Could also be a couple big dropping resistors and a couple zeners, but that doesn;t sound very Panasonic-ish to me.
There may be only one +/-15v source, and those two ICs are powered through a coupe of isolation resistors, and the one on the + side has failed. I see that a lot on mixers, +/-15 will run channel to channel, and the ICs on each channel will receive their 15v rails through a pair of 10 ohm or 100 ohm resistors. Its for decoupling. It is just a possibility.Education is what you're left with after you have forgotten what you have learned.Comment
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Ramsa made by Panasonic. However call Panasonic and they pretend that they never heard of it.Originally posted by lowell View Post
There IS one Ramsa tech left. But Panasonic delights in charging people obscene prices for schematics and manuals. IF you can get them to admit that Ramsa exists.Comment
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Ramsa is a Matsushita company as is Panasonic. When I have called Matsushita PArts in the past, then have sent me what I needed for Ramsa products.
SOme companies charge for their manuals. Yamaha makes excellent manuals that are worth every penny. I found Roland manuals to be comprehensive and very useful. Even if you find freee schematics, manuals often include diagnostics and adjustment procedures and other useful information. I have purchased Ramsa manuals. I have one for a WR8112/8118 (if I recall the number right) that is about 40 pages, with complete specs, comprehensive parts lists, layout drawings which include trace art, and of course the schematics, which were on 11x17 fold-outs. That is worth paying for. How much of my time is $25 worth? WIll I spend more than that time fucking around trying to do without documentation? Always get the right tool for the job. Often, that includes service manuals.
People who find old Kustom schematics and want to sell them at $15 a pop are cheap bastards, I'd agree. But when Yamaha sells a whole damn book about some complex piece of gear and wants $25, I don;t find that obscene at all. Sure I;d rather get it for free, but the I'd prefer Outback cook me a steak for free too.Education is what you're left with after you have forgotten what you have learned.Comment
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They will not sell you a single part, not even a knob, without a part number.
So that part number is going to cost you $25, no matter what.
And, it's fun when they break it into multiple manuals.....$25 EACH.
They will not look up a part number for anyone, not even the authorized service center techs.
I know, I used to work for one.
There is a difference between PV and Ramsa, isn't there?
Although the equipment is not bad, and built pretty good actually, and the parts were cheap,
but the customer service strategy sucks.Comment
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