Sony TA-F6B PSU repair

johnm · 02:14 PM

Hi folks!

I have a Sony TA-F6B which I recently was given, virtually for free. It's a lovely looking - and by all accounts sounding - amplifier so I'd like to get it working again.

The last owner said it made a loud popping sound one day, and hasn't worked since. After taking the amp apart, it's obvious the owner before him either did some tinkering, or gave it to a tech who cut a few corners...!

I have traced the problem to the PLPS (Pulse Locked Power Supply - basically a late 70s Sony SMPS I think). A heatsink/clamp to four power transistors was not replaced by previous owner/tech so in the end two of these met their maker! Worse he replaced two of the transistors with a different make, and all four are meant to be hFE/batch matched. There is also evidence of lifted solder pads and a jumper wire too in the following pics:

Here's what it should look like with the missing clamp:

http://picasaweb.google.com/895720/S...51198508682210

So basically, I need to know what an ideal modern substitute for the 'R' hFE grade, and 'O' hFE grade Sanken 2SC2023 power transistor would be please, as the original devices seem next to impossible to get hold of now.

Any help/advice would be gratefully received

Thanks,

- John

johnm · 14th January 2011, 03:08 PM

The original specs for this part:

2SC2023 pdf, 2SC2023 description, 2SC2023 datasheets, 2SC2023 view ::: ALLDATASHEET :::

jaycee · 14th January 2011, 05:27 PM

Those transistors with gold leads are bad news... look to replace them.

Fortunately there should be loads of suitable TO-220 transistors now that SMPS are all the rage. Fairchild are probably best to look at for this. The high Vceo and fast(ish, for those days) switching speed will be whats important here.

jaycee · 14th January 2011, 05:52 PM

Actually keeping it simple, TIP50 looks like it will be suitable

Mooly · 14th January 2011, 05:52 PM

What about using something like BUT11AF (plastic insulated TO220) that is common in TV and SMPS use.

Mooly · 14th January 2011, 05:56 PM

Also just to add that 99% of SMPS failures are down to electroylitics developing high ESR (drying out).

It would be a big help to see the circuit... those 2335's were used from memory in the Sony SLC9 and SLC7 VCR PSU's

Mooly · 14th January 2011, 06:00 PM

Free manual here,
Sony | Owners Manuals, Service Manuals, Schematics, Free Download | HiFi Engine

johnm · 06:12 PM

Thanks for the suggestion guys - much appreciated

I'm really no more than a 'solder by numbers' DIY guy so lack the knowledge about what parts are best to substitute.

The caps on the main board will be replaced with Panasonic and Rubycon 105C long life types (mostly FC/FM and ZLH low esr types).

Here's a scan of the PSU (or PLPS!):

- John

johnm · 06:14 PM

Q609-612 are the 2SC2023-O or Rs

Q601 & Q613 (the two on the side that are red in the pictures a few posts above) are the 2SC2023-Rs

- John

johnm · 14th January 2011, 06:07 PM

Quote:

Originally Posted by Mooly

Free manual here,
Sony | Owners Manuals, Service Manuals, Schematics, Free Download | HiFi Engine

Many thanks for that link Mooly but I already have the full service manual which I had to pay to download - the Hi-Fi Engine one is missing many pages.

14th January 2011, 01:53 PM	#1
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Sony TA-F6B PSU repair Hi folks! I have a Sony TA-F6B which I recently was given, virtually for free. It's a lovely looking - and by all accounts sounding - amplifier so I'd like to get it working again. The last owner said it made a loud popping sound one day, and hasn't worked since. After taking the amp apart, it's obvious the owner before him either did some tinkering, or gave it to a tech who cut a few corners...! I have traced the problem to the PLPS (Pulse Locked Power Supply - basically a late 70s Sony SMPS I think). A heatsink/clamp to four power transistors was not replaced by previous owner/tech so in the end two of these met their maker! Worse he replaced two of the transistors with a different make, and all four are meant to be hFE/batch matched. There is also evidence of lifted solder pads and a jumper wire too in the following pics: Here's what it should look like with the missing clamp: http://picasaweb.google.com/895720/S...51198508682210 So basically, I need to know what an ideal modern substitute for the 'R' hFE grade, and 'O' hFE grade Sanken 2SC2023 power transistor would be please, as the original devices seem next to impossible to get hold of now. Any help/advice would be gratefully received Thanks, - John Last edited by johnm; 14th January 2011 at 02:14 PM.

14th January 2011, 05:52 PM	#5
Mooly diyAudio Moderator Join Date: Sep 2007	What about using something like BUT11AF (plastic insulated TO220) that is common in TV and SMPS use. __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

14th January 2011, 05:56 PM	#6
Mooly diyAudio Moderator Join Date: Sep 2007	Also just to add that 99% of SMPS failures are down to electroylitics developing high ESR (drying out). It would be a big help to see the circuit... those 2335's were used from memory in the Sony SLC9 and SLC7 VCR PSU's __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

14th January 2011, 06:00 PM	#7
Mooly diyAudio Moderator Join Date: Sep 2007	Free manual here, Sony \| Owners Manuals, Service Manuals, Schematics, Free Download \| HiFi Engine __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

14th January 2011, 06:03 PM	#8
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Thanks for the suggestion guys - much appreciated I'm really no more than a 'solder by numbers' DIY guy so lack the knowledge about what parts are best to substitute. The caps on the main board will be replaced with Panasonic and Rubycon 105C long life types (mostly FC/FM and ZLH low esr types). Here's a scan of the PSU (or PLPS!): - John Last edited by johnm; 14th January 2011 at 06:12 PM.


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

14th January 2011, 03:08 PM	#2
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	The original specs for this part: 2SC2023 pdf, 2SC2023 description, 2SC2023 datasheets, 2SC2023 view ::: ALLDATASHEET :::

14th January 2011, 05:27 PM	#3
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Those transistors with gold leads are bad news... look to replace them. Fortunately there should be loads of suitable TO-220 transistors now that SMPS are all the rage. Fairchild are probably best to look at for this. The high Vceo and fast(ish, for those days) switching speed will be whats important here.

14th January 2011, 06:05 PM	#9
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Q609-612 are the 2SC2023-O or Rs Q601 & Q613 (the two on the side that are red in the pictures a few posts above) are the 2SC2023-Rs - John Last edited by johnm; 14th January 2011 at 06:14 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
schematics sony Ta- F6B	max29	Solid State	5	17th March 2011 07:36 PM
SONY TA 70, repair help needed	jojospecial	Solid State	2	5th November 2008 08:15 PM
Sony TA-AV670 amp repair	calum112	Solid State	2	27th March 2007 08:38 PM
Sony TA-N1 and TA-NR1, how do they sound?	lumanauw	Solid State	0	28th November 2006 01:51 AM
FS: Sony "Esprit" TA-E901 and TA-N901 pre and power amp	MJR	Swap Meet	1	6th December 2003 07:55 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read