Alternative IC to SVISTK2028(B) ??

[Markoneswift]

Hi all,

A friend of mine has a Technics SA-103 receiver and he would really like to get it going again - it currently has one dead channel. I've traced out as much as I can in terms of voltages to the IC and everything looks good up to the input, but then nothing coming out.

I had a Google for alternatives to the 2028 but there doesn't seem to be one - I know from experience that with the 461,463 and 465 they are pin compatible but 2028 doesn't seem to have any options.

Can anyone help with this ? Thanks

 

[KentTeffeteller]

No generic alternatives I know exist.

 

[Markoneswift]

I may have a line on some genuine 2028's from a fellow AK'er - we shall see

 

[SVI2004A]

STK2038

 

[SVI2004A]

there are 5 clusters on all these series

(1-5) ch1 power amp (6,7) ch1 protect functions, (8,9) Ground. (10,11) ch2 protect functions, (12-16) ch2 power amp

This list will work as the power amplifiers and ground are the same function.... the protect functions may or may not operate the same way, though I've seen schematics indicate some compatibility

STK2048
STK 2048IV (complimentary symmetry) (synchro bias)
STK2058IV (more powerful version of STK2048IV)
SVI2003 (Technics new class A) this ic is larger physically.
SVI2004 (as above - more power)

Change in protect circuit from STK20X8IV --> SVI200X - refer service manual SU-V2X (this model was released with both types of power ic)

In the later 90s did once put a SK2058IV in a SU-Z1 (STK2028) with no problem...

 

[SVI2004A]

I can still get STK2028 and STK2038 new locally but I don't know for how much longer (non counterfeit)

 

[Markoneswift]

I can still get STK2028 and STK2038 new locally but I don't know for how much longer (non counterfeit)

What kind of cost are we talking for these things mate ? The Sa-103 is not exactly TOTL and I'm unsure who much dough my friend wants to put into it.

Thanks for your help

 

[SVI2004A]

I get these for $20AUD + postage... think I have 2 on hand ATM... I tend to keep some stock of these before they become unobtanium-

Source Wes components www.wescomponents.com.au

 

[tNomade]

Hi there.
I got a Technics sa-103, power module missing, so thank you for the replacement list. unfortunately locally any of them are available. Also I've seen some in ebay but i'm affraid they are counterfeits... BTW have you successfully repplicated a module? I have seen a kind of sample of power output at the AN7062 which feeds signal to stk2028.

 

[SVI2004A]

Haven’t had to replicate - my supplier still has these non counterfeit

 

[tNomade]

Did write wrong the ic number. It is AN7060 and it's datasheet shows a sample implementation

Unfortunately I couldn't find around here a brand new genuine stk2028 or compatible. (BTW, I tried to browse at WES they required to be subscribed so, do have to wait for approval?)
An alternative is to pull from another equipment, thank you for the list you wrote (any update?) I wouldn't like to spend too much on repairing it (did get the AS-103 by 15USD)

 

[tNomade]

In your experience, which differences have if you replace the stk 2028 with the 2038, 2048 in terms of audio quality, output power or any? increases service time? harder to damage the amp? have you tried counterfeits? what are the downsides?

I know I know, too many questions... but I am interested... I'd like to repair my sa 103
Regards

 

[SVI2004A]

I recommend upping the chip... sonically 2028-2038 and 2048 won’t be different, power output won’t go up (power supply)
But the higher powered chips will prove more robust...

 

[tNomade]

Thank you. Also I did check WES after a while they redirected me to Wagner online STK2028 22USD, STK 2038 30USD (kinda expensive). Also surfing on the net fund UTSOURCE NET,is about 8 and 9 USD respectively, they claim their ICs are SANYO. What do you think?

By the way, have you tried counterfeit stk?