Katana - HELP NO SPEAKER OUTPUT AFTER SWAP OUT.!

Started by majellin, February 12, 2018, 11:24:11 AM

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majellin

because of the isolated ground output of the Katana power amp section, what could possibly happen if the pos or neg leads touch ground or the amp chassis?
after speaker change I can only now get sound from the rec out.
no internal speaker sound.
I re-installed the original Katana speaker and still nothing.
HELP!!!  what did I do??

admin

CAUTION - If ANY Speaker (+) wire or (-) wire touch each other - or Chassis ground while powered ON -  - you fry the Katana Power amp




gumtown

You will be requiring a replacement power amp module.  :o

If you are techy inclined, you could try replacing the amplifier IC chip your self.
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

majellin

ok so where can I get the Katana 50 power amp module IC replacement?

KeldAmpworks

I did a teardown of the Katana 50. But sadly I didn't remove the plate to identify the output IC.

http://www.ampworks.co.uk/experiments/boss-katana-mod-midi-mod-rec-mod

It's a 15 pin vertical mount IC. Roland have used the TDA series monolithic PAs before on the Cube range. So I'm going to guess TDA7296 (60W) or TDA7295 (80W).

Not the easiest chip change, if you're in the UK you're welcome to send it over to my repair shop. :)

vtgearhead

A Roland repair center can probably sell you the entire output board, but would be much more cost effective to simply replace the IC.

admin

#6
Quote from: snhirsch on February 13, 2018, 05:04:25 AM
A Roland repair center can probably sell you the entire output board, but would be much more cost effective to simply replace the IC.

Since 2016 , In USA all repairs are now performed by Boss US in Ontario, California and they no longer sell parts to customers
(Ive tried)

Try your luck

You must register the product and have a Backstage Pass
https://www.boss.info/us/support/

majellin

how can I test the ic amp chip
to be sure?  it's a TDA7293
I don't see any burned spots or fried circuits on the board anywhere. it doesn't appear to look blown.
thank you

KeldAmpworks

It doesn't have to look blown to be blown sadly.

http://www.st.com/en/audio-ics/tda7293.html

Good to know boss have built some power redundancy in (100W chip for 50W amp)

Ask some one who is experienced working on live electronics to check for input signal on pins 2 or 3. If there's signal there but nothing coming out, then the power amp chip is probably dead.

Without in any way wanting to sound rude, I'm assuming from your questions you probably oughtn't to work on live electronics, so for your own safety please take it to a good repairer. :)

The unit is of course mains powered and therefore potentially lethal.

Good luck with getting it sorted.

admin

#9

admin

Quote from: majellin on February 12, 2018, 11:24:11 AM
because of the isolated ground output of the Katana power amp section, what could possibly happen if the pos or neg leads touch ground or the amp chassis?
after speaker change I can only now get sound from the rec out.
no internal speaker sound.
I re-installed the original Katana speaker and still nothing.
HELP!!!  what did I do??