Replies to This Discussion

Permalink Reply by BrianQ. on May 13, 2019 at 2:26pm

Have you tried Yamaha website?

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Permalink Reply by Paul Craig on May 13, 2019 at 8:10pm

If the power transformer is bad, it will cost more to fix it than to buy another.

I had a Behringer 10watt guitar amp that did the same thing. I removed all the old electronics(leaving the speaker and metal chassis) and made a 1watt 9volt Ruby amp and installed it. Works great and is the perfect little practice amp. It actually sounds better than the amp I replaced.

You could buy one of those 2.5watt amps and a Psycho Kob from Gitty and wire them up using that cabinet and speaker. I use a walwart instead of battery.

You may also find a similar small amp at a local pawn shop for little money.

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Permalink Reply by KOOL DOG HOOCH on May 13, 2019 at 10:48pm

I'm mainly looking for the rectified voltage. Yamaha can't or won't help. I have a couple salvaged transformers that possibly could work. Not a big deal!

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Permalink Reply by Timothy Hunter on May 14, 2019 at 12:21am

photo of the dead transformer? are there any markings on it? are you sure it is the transformer and not the diode bridge in the rectifier?

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Permalink Reply by KOOL DOG HOOCH on May 14, 2019 at 12:55am

No photos or markings(first thing I looked for, only qc sticker). I gutted the transformer to make a pick up. The transformer's primary side was fried. The rectifier bridge is fine(tested with ohm meter). In hindsight I'm thinking I should have rewound the transformer pita but doable. I may hook a 9v a.c. wall adapter up and see what happens, at this point nothing to loose. Really would like to use a 12 v gel battery for portability.

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Permalink Reply by Paul Craig on May 14, 2019 at 8:45am

Get the model number off the main chip and google it for specs. That way you find out the operating voltage, it could be 9volts, 12volts or 18volts DC.

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Permalink Reply by KOOL DOG HOOCH on May 15, 2019 at 2:45pm

Its a tda2030a, from what I've read 6- 36 volts. So I think I'll split the difference and go with 12 volts and keep it on the safe side. What's your thoughts?

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Permalink Reply by Timothy Hunter on May 16, 2019 at 2:43am

TDA2030A  data sheet here https://www.st.com/resource/en/datasheet/cd00000129.pdf

says 18W output into 4 ohm load with +- 16V  . were there 2 windings on the secondary?  it looks like it can be hooked up to a single supply but the chart of output power to supply voltage suggests yoy will need around 30V DC to get 15W into a 4 ohm load. or around 36 V if it is an 8 ohm load.. chart starts at 24V with 10W into a 4 ohm load. so you could series 2 gel cells for 24 volt it would work but not push the amp

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Permalink Reply by KOOL DOG HOOCH on May 16, 2019 at 4:40am

I could do 3 gel cells for 36 v, I don't plan on cranking up the amp and grinding away!

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Permalink Reply by Paul Craig on May 16, 2019 at 7:55am

good ideas

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Permalink Reply by Paul Craig on May 14, 2019 at 8:47am

When my amp went out, it also fried some output caps along with the overheated chip. So have a good look at all the components and check them with a voltmeter if you have one.

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Permalink Reply by KOOL DOG HOOCH on May 14, 2019 at 9:45am

Damn good idea about the specs for the chip, didn't even think about that. Thanks all other components check out. If it had been the secondary side I would probably scraped the unit.

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