Yamaha YST-SW216 Problem

[TLS Guy]

I taken to lab but presently oscilloscope not available, so one of professor checked output to the speaker and found 1.34v so STK is damaged.
Presently in my place I checked all shops not available
Can u suggest me any other equivalent ic.

There is no equivalent. Nothing cross references. That is what I found out at the start of this. Mouser don't have it. It is listed on Digi-Key,t he world's largest supplier of electronic components as obsolete and no longer available. So they will never be available again.

This is the problem with ICs. There is usually only 1 production run and when they are done they are done.

Now you have made a good effort, and it seems you are in school.

So this is the end of the road for you unless you want to design a totally new IC power amp to run off that power supply as a class project. Now you are above my pay grade, but may be one of your professors can help. The difficult part will be duplicating the motional feedback part as we do not know its characteristics. So this is probably a next to impossible endeavor.

Its new sub time, I'm afraid.

 

[PENG]

There is no equivalent. Nothing cross references. That is what I found out at the start of this. Mouser don't have it. It is listed on Digi-Key,t he world's largest supplier of electronic components as obsolete and no longer available. So they will never be available again.

This is the problem with ICs. There is usually only 1 production run and when they are done they are done.

Now you have made a good effort, and it seems you are in school.

So this is the end of the road for you unless you want to design a totally new IC power amp to run off that power supply as a class project. Now you are above my pay grade, but may be one of your professors can help. The difficult part will be duplicating the motional feedback part as we do not know its characteristics. So this is probably a next to impossible endeavor.

Its new sub time, I'm afraid.

I missed many posts in a few days but it seemed like you have it narrow down to the IC amp. Is this the one he needs?
https://www.ebay.com.au/itm/STK404-070-Original-New-Sanyo-Power-Integrated-Circuits-/121057024423?oid=362311002414

Otherwise he could buy the whole sub from ACFL
https://www.accessories4less.com/make-a-store/item/yamystsw216bl/yamaha-yst-sw216-10-100-watt-powered-subwoofer-black/1.html

No end of road yet, just money!!

 

[TLS Guy]

I missed many posts in a few days but it seemed like you have it narrow down to the IC amp. Is this the one he needs?
https://www.ebay.com.au/itm/STK404-070-Original-New-Sanyo-Power-Integrated-Circuits-/121057024423?oid=362311002414

Otherwise he could buy the whole sub from ACFL
https://www.accessories4less.com/make-a-store/item/yamystsw216bl/yamaha-yst-sw216-10-100-watt-powered-subwoofer-black/1.html

No end of road yet, just money!!

Yes, that is the one he needs. He had better hurry, there are only 10 left out of the 33 that supplier in Florida had.
I would advise he buys 2 as insurance!

The Australian seller is already sold out.

 

[M Code]

U must have missed this post..
The IC is available from Amazon...

2. Replacement part is available for $15 from Amazon.
https://www.amazon.com/STK404-140-STK404140-STK404-140S-1pc/dp/B00YAP2EE6

However I think U are in Europe, is this correct??

Just my $0.02...

 

[TLS Guy]

U must have missed this post..
The IC is available from Amazon...

2. Replacement part is available for $15 from Amazon.
https://www.amazon.com/STK404-140-STK404140-STK404-140S-1pc/dp/B00YAP2EE6

However I think U are in Europe, is this correct??

Just my $0.02...

That's the wrong chip. He needs STK404-070. Peng found the right one on eBay. None left in the supply houses. It is obsolete.

 

[M Code]

IC product is obsolete but limited stock still available..
A China distributor we work with occasionally has 17 pcs in stock, they deal in overstock and discontinued silicon parts.. A few years ago, we bought 25K of a Sanyo video processor IC for a major USA AVR brand from this distributor so they could build AVRs for the 4th qtr. The ICs were not available due to an earthquake in Japan which had severely damaged the Sanyo IC factory. The replacement IC had same stock # but a different suffix, as it was for the OSD menu/fonts for another well-known brand. We got samples of the IC, rewrote the AVRs' firmware to handle the revised font library and went into production for the crucial 4 th qtr. In appreciation for saving the 4th qtr, the president for this well-known AVR brand gave me a sizable $ bonus for the find...

Just my $0.02...

 

[lovinthehd]

IC product is obsolete but limited stock still available..
A China distributor we work with occasionally has 17 pcs in stock, they deal in overstock and discontinued silicon parts.. A few years ago, we bought 25K of a Sanyo video processor IC for a major USA AVR brand from this distributor so they could build AVRs for the 4th qtr. The ICs were not available due to an earthquake in Japan which had severely damaged the Sanyo IC factory. The replacement IC had same stock # but a different suffix, as it was for the OSD menu/fonts for another well-known brand. We got samples of the IC, rewrote the AVRs' firmware to handle the revised font library and went into production for the crucial 4 th qtr. In appreciation for saving the 4th qtr, the president for this well-known AVR brand gave me a sizable $ bonus for the find...

Just my $0.02...

So are you saying the IC available from Amazon will still work in this instance despite the different suffix?

 

[M Code]

So are you saying the IC available from Amazon will still work in this instance despite the different suffix?

No...
The original part # STK404-070 is available..
The STK404 -140 part will not substitute, it has a different case & mounting centers...

Just my $0.02...

 

[21balu]

I ordered STK 404-70 on 5days back today received and replaced with good soldering equipments,
Tried out found working satisfactory.
Good experience with STK.
Now planning to upgrade with little big size wooden box.
Thank you for your support.

 

[M Code]

A couple of points...
1. Make sure the mounting screws for the 404-70 are torqued down snug, this crucial for proper thermal control
2. Be careful about overdriving the subwoofer, the 404-70 does not stand up well when driven into distortion

Just my $0.02...

 

[21balu]

Recently my Yamaha YST-SW216 not working due to power fluctuations, i opened and checked transformer found fuse is damaged same replaced with same rating fuse, still not working also transformer primary voltage is showing 110vac but secondary only 9vac, i refered schematics but i can't find what is the output of power transformer, if you can tell me ill try to solve problem with same rating transformer or smps. Thank you

 

[TLS Guy]

Recently my Yamaha YST-SW216 not working due to power fluctuations, i opened and checked transformer found fuse is damaged same replaced with same rating fuse, still not working also transformer primary voltage is showing 110vac but secondary only 9vac, i refered schematics but i can't find what is the output of power transformer, if you can tell me ill try to solve problem with same rating transformer or smps. Thank you

Funnny, I was just wondering the other day when you would be back with more problems with that unit.

My first thought is that the transformer is fine, but due to damage the load is excessive. It would be highly unusual for a transformer to fail like that. A winding going open circuit is almost always the failure mode.

The first thing to do is to isolate the transformer and measure the voltage unloaded.

Usually in the sort of events you describe, practically every solid state device in the unit is destroyed and then some.

The circumstances of the failure are very discouraging for getting this unit back up.

 

[21balu]

I opened secondary terminals and checked but voltage not showing but I again checked found transformer input side a small pcb which is problem, I soldered directly to the transformer input terminals found 52.5vac and from centre tap 26-0-26.

 

[21balu]

Thanks I have to tried out.

 

[21balu]

Triedout working satisfactory.
Coincidence is that three problems together
1. Power card also damaged
2. Power transformer pcb track is damaged
3. Fuse also damaged

 

[TLS Guy]

Triedout working satisfactory.
Coincidence is that three problems together
1. Power card also damaged
2. Power transformer pcb track is damaged
3. Fuse also damaged

So if I understand you correctly it is working. Is that correct. If the problem has ended with the power cord, fuse and switch board you are very lucky. I could do with some of that luck?

 

[M Code]

In checking the YST-SW216 schematic for the 120V version closely, the power transformer #X4814A00 does have an external 1.6A fuse, plus an internal circuit breaker within the transformer structure. The internal circuit-breaker is required by UL/CSA, and is not user-replaceable if blown in a rare case the transformer is bricked...

Just my $0.02..

 

[21balu]

Yes working Normal.
As you said i also think that T/F is bricked but after disconnect T/F fully from circuit and checked coil resistance found 2-3ohms respectively, secondary end to end is 10 ohms, so the problem is Power T/F input side small pcb there is a invisible broken contact under T/F input soldered contact.

Yesterday night checked working in good condition
Thanks for your help, if you not not replay i try to replace T/F.

 

[21balu]

Thanks to all Especially TLS.

 

[U20417]

Yes, that is the one he needs. He had better hurry, there are only 10 left out of the 33 that supplier in Florida had.
I would advise he buys 2 as insurance!

The Australian seller is already sold out.

I have the YST-SW216. I am in the USA. I have 32vdc on the RY1 relay. So it looks like if I can find the correct IC I might be able to replace it.

My chip is STK404-070. Below that number down near the pins I have an N on the left side and D6E06 on the right side. I have found some STK404-070 chips from Canada. These chips have C inplace of N and a different lot number D9A26. Can I use the Canadian chip to replace my USA chip?

Thank you in advance for your help on this matter.