Kenwood TA2030/TA2040 output devices

[acmmty]

I need to buy some modules for my Basic M1A
I have seen that there are two types of ICs: Some with the codes of the upper right corner printed with white ink and others with the codes with engraved letters.
Those of white ink are in the cheap publications of the great auction site. Those that are engreved appear mostly in images of apparently unrepaired systems, in used parts and in good stores.

Are all ICs with white ink fake?
Has anyone used this cheap replacements successfully?
Do you know any way to distinguish good devices from bad ones?

Any recommendation is appreciated.
Thank you

 

[tarior]

Those aren't outputs. They are switching chips that act as commutators between the low and high rail voltages for the output drive.
The service manual tells how to determine if they are functioning.

Same principle of operation as the KA-1100SD.

http://audiokarma.org/forums/index.php?threads/kenwood-ka-1100sd-it-can-be-fixed.818035/

 

[acmmty]

Thank you, tarior.
Yes, the TA2030 is a comparator / switch, the TA2040 is a module that contains all the rest of the output section but that's not my point. Sorry if I do not explain myself. I do not speak English very well.

My question is if you can consider all the chips with the codes painted in white as not OEM and if someone has had good results with them.

Some examples:
This seems copied from a brochure. (Engraved codes, look like the TA2040 have golden letters).

These are the cheap replacements with white ink codes

[/quote]

 

[petehall347]

these might be ok but silly money . https://www.littlediode.com/components/TA2040.html

 

[tarior]

I personally have never sat down and compared these to try and identify counterfeit devices, so I'm not much help there.
Are you absolutely certain that the 2030/2040 is the problem?

 

[petehall347]

one way is crack them open and compare build quality to know original

 

[acmmty]

these might be ok but silly money . https://www.littlediode.com/components/TA2040.html

Yes. I asked them and they answered me: Lead time is 7 days and they are sourced from the Far East.

 

[petehall347]

ask these for quality issues ..http://nikkoe.com/catalogsearch/result/?q=TA2040 i have never bought these modules from anywhere as it happens ....but have bought mosfets and rare transistors from them with no issues at all .
your best is to see if it can be copied with discreet components .. i know some of the stk modules are now available in kit form .

 

[tarior]

ask these for quality issues ..http://nikkoe.com/catalogsearch/result/?q=TA2040 i have never bought these modules from anywhere as it happens ....but have bought mosfets and rare transistors from them with no issues at all .
your best is to see if it can be copied with discreet components .. i know some of the stk modules are now available in kit form .

I've had good luck with them as well with some hard to find Pioneer tuner chips, however, I haven't bought anything from them in the last few years.

 

[petehall347]

i haven't either . i dont find much time these days for playing with electronics as it happens . i really must get back in the shed/workshop for some hands on ..

 

[acmmty]

tarior:
Yes one TA2040 and other related components are bad.
I recently bought this Basic M1A with one bad channel, cheap and aesthetically well-maintained.
I opened it and I see that I was not the first one there. The seller said it was "never repaired". It means "history unknown".
The 4 modules have the white letters.
In the working channel IC4 (TA3020) have a TA2031 installed, the solders not looks original and the font style in the ship is different. (previous repair?)

Looking again on google images I find an identical to mine BASIC M1A with white letters and the TA2031 module on the left. This gets interesting.

https://www.olx.pl/oferta/zamienie-koncowka-mocy-kenwood-basic-m1a-CID99-IDj5O0P.html

PD:
I already checked and this is not my BASIC M1A. This is the AC 110V/220V version and mine is only AC 120V

 

[acmmty]

ask these for quality issues ..http://nikkoe.com/catalogsearch/result/?q=TA2040 i have never bought these modules from anywhere as it happens ....but have bought mosfets and rare transistors from them with no issues at all .
your best is to see if it can be copied with discreet components .. i know some of the stk modules are now available in kit form .

Thank you very much but that is really a TA2040AP DIP16PIN

 

[acmmty]

Hi there.
Pleased to be making progress on my basic M1A
After thinking about it, I gave an opportunity to the cheap china parts of the big auction site. I bought two pairs of each; 1 new pair and 1 used pair. All the modules looks and weight exactly the same.

After checking all the parts in the amplifier and with all the bad parts replaced, I installed the new pair and the amplifier works and sounds very good.
.
As some commented some time; Edevil is not always devil (Or somtehing like that)

1.- Old part up. new part down.
2.- Power vs THD+Noise. Yellow right, light blue left
3.- Frequency response
4.- THD+Noise vs Frecuency

I just wanted to close this post and tell you my experience. Thank you all for your answers and your help.

Alex.