Tapco Thump TH-15A Amplifier repair

MrChips

Joined Oct 2, 2009
30,707
Two separate tests to perform with DSP board removed:

Test 2A -Jumper from 1A to 2A via 10μF cap.

Test 3A - Jumper from 1A to 3A via 10μF cap.

TAPCO MACKIE TH-15A Preamp photo TP1A.jpg
 

MrChips

Joined Oct 2, 2009
30,707
Both test passed successful..☺
So the problem is on the DSP board. It could also be a bad U3, WM8569 on the preamp board.
Do you have access to an oscilloscope?
Even with an oscilloscope this is not a simple problem to diagnose.

The quickest solution is to purchase a replacement DSP board.
 

MrChips

Joined Oct 2, 2009
30,707
If you just want to get the THUMP running without the DSP board, you can design and build an electronic crossover with opamps and just bypass the DSP board.
 

Thread Starter

Roque

Joined Sep 16, 2014
158
So the problem is on the DSP board. It could also be a bad U3, WM8569 on the preamp board.
Do you have access to an oscilloscope?
Even with an oscilloscope this is not a simple problem to diagnose.

The quickest solution is to purchase a replacement DSP board.
Cool...had a guy pick up his phonic speaker from me and was mentioning to him about the mackie..he says he has a busted one similar model giving a distorted funny output...he asked me if i wanted parts from it...hoping his dsp board is ok..what you reckon Mr Chips..??
 

Thread Starter

Roque

Joined Sep 16, 2014
158
Cool...had a guy pick up his phonic speaker from me and was mentioning to him about the mackie..he says he has a busted one similar model giving a distorted funny output...he asked me if i wanted parts from it...hoping his dsp board is ok..what you reckon Mr Chips..??
If its working then could buy it off him..
 

Thread Starter

Roque

Joined Sep 16, 2014
158
If you just want to get the THUMP running without the DSP board, you can design and build an electronic crossover with opamps and just bypass the DSP board.
Will try with the other chaps dsp board...if not..not sure if its worth the effort ...building another circuit...not much of a designer i am.... would the crossover sit between 1A and 3A or 1A and 2A? ...maybe i might find online schematics..☺ if i do manage to get my hands on the other dsp board and it works will let you know...thanks again Mr Chips for all your help...should call you Mr Guru from now...hope we catch up again ..let me know where the crossover would sit between ???? Cheers and God bless mate. You are a legend.
 

MrChips

Joined Oct 2, 2009
30,707
Cool...had a guy pick up his phonic speaker from me and was mentioning to him about the mackie..he says he has a busted one similar model giving a distorted funny output...he asked me if i wanted parts from it...hoping his dsp board is ok..what you reckon Mr Chips..??
Get it from him for parts (for a reasonable price, under AUD$50? What is a used working TH-15A worth, AUD$400?).
If you get lucky you just might get both working again.
 

Thread Starter

Roque

Joined Sep 16, 2014
158
Get it from him for parts (for a reasonable price, under AUD$50? What is a used working TH-15A worth, AUD$400?).
If you get lucky you just might get both working again.
Yes would be around $400AUD....just sent him a text...hehehe..
 

MrChips

Joined Oct 2, 2009
30,707
Actually, you wouldn't need U4.
The crossover would fit between TP1 and TP6 and TP7 on the schematic shown on post #30.
The crossover frequency is 3kHz.

The drawback is the EQUALIZER control would be ineffective since this is done by the DSP. Only the LEVEL control would work.

You can modify U4-B and make it your LF filter.
You just might be able to hack U4-A and turn it around to make a HP filter.
 

Thread Starter

Roque

Joined Sep 16, 2014
158
Actually, you wouldn't need U4.
The crossover would fit between TP1 and TP6 and TP7 on the schematic shown on post #30.
The crossover frequency is 3kHz.

The drawback is the EQUALIZER control would be ineffective since this is done by the DSP. Only the LEVEL control would work.
Okie.....hmmm.. lets see what comes up ...we done our best thanks to you..☺ keep up the good work you doin..cheers
 
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