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  #31  
Old 10-17-2015, 09:14 PM
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eBay UK has a listing for the magazine:

http://www.ebay.co.uk/itm/TELEVISION.../161859718754?

but the seller doesn't ship internationally.
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  #32  
Old 10-18-2015, 08:32 AM
Alastair E Alastair E is offline
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OK Maybe I wasn't clear.....

All thats required is to Duplicate the Drive Circuit from the Donor set, the components around the drive Transformer, and Drive Transistor any series or parallel caps and resistors, these may affect the drive transformer tuning, and the components between the drive Tx and the Horz-Out Transistor.
Goes without saying--ALL the components of the original Gate Drive circuit of the SG will need to be removed.

The Horiz Out Transistor in any conventional--And these Sony sets--(Or GTO, MOSFET, IGBT--Whatever),--
is used as a switch, and as such is driven hard on each time its needed,(Important) the timing derived by the horiz osc/sync circuit, at 15.625KHz in case of UK sets....

The Transistor Must be driven Hard On (Taken Care of by the Drive Tx and its Base components --or it will dissipate excessive power in form of heat and self-destruct....

Ive not ever seen any 'impedance issues' --a Transistor driven hard on has low V C-E anyway--just like its Sony GTO equivalent.
No apparent issues at all.

Providing a suitable Horiz Output Transistor is chosen that has a suitable Voltage and Current Rating, is Driven accordingly--Then it will work.
(There's NO reason you couldnt use an IGBT or MOSFET if its a 'Horiz-Out' type from a very recent donor set....
I see no real issues providing the Donor drive scheme is applied in each case)

All thats needed is to COPY the Design of the Drive Circuit from the Donor set--Schematics for both are needed for this. The last one I converted--was over 25 years ago, but clearly remember it being very easy!

The UK Publication will refer to donor parts from UK sets with specific values of components For those parts, as such would not be suitable for USA engineers, and also worth considering the differences in tuning for the different line frequency between UK and US format sets.....
Stick to Donor parts from what you have around in your country--Follow the drive schematic of the donor--you wont go far wrong!

Really IS a Junk-Parts conversion job, using scrap chassis parts.....

I used a variety of different donor set parts, from Philips G8 and Thorn drive transformers--Whatever I had around actually. I doubt there would be any of these donors around in the US!
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  #33  
Old 10-18-2015, 09:58 AM
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Quote:
Originally Posted by Findm-Keepm View Post
eBay UK has a listing for the magazine:

http://www.ebay.co.uk/itm/TELEVISION.../161859718754?

but the seller doesn't ship internationally.
I received a reply from the seller - he now ships to the US.

But, from Alistairs description above, it isn't a mod so much as a mutilation/transplant/conversion of the horizontal sweep circuit of one transistorized set into a Sony. To me, a modification is a value change here or there, perhaps adding one or two components, but major surgery? Not for me.
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  #34  
Old 10-18-2015, 10:44 AM
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Quote:
Originally Posted by Alastair E View Post
OK Maybe I wasn't clear.....

All thats required is to Duplicate the Drive Circuit from the Donor set, the components around the drive Transformer, and Drive Transistor any series or parallel caps and resistors, these may affect the drive transformer tuning, and the components between the drive Tx and the Horz-Out Transistor.
Goes without saying--ALL the components of the original Gate Drive circuit of the SG will need to be removed.

The Horiz Out Transistor in any conventional--And these Sony sets--(Or GTO, MOSFET, IGBT--Whatever),--
is used as a switch, and as such is driven hard on each time its needed,(Important) the timing derived by the horiz osc/sync circuit, at 15.625KHz in case of UK sets....

The Transistor Must be driven Hard On (Taken Care of by the Drive Tx and its Base components --or it will dissipate excessive power in form of heat and self-destruct....

Ive not ever seen any 'impedance issues' --a Transistor driven hard on has low V C-E anyway--just like its Sony GTO equivalent.
No apparent issues at all.

Providing a suitable Horiz Output Transistor is chosen that has a suitable Voltage and Current Rating, is Driven accordingly--Then it will work.
(There's NO reason you couldnt use an IGBT or MOSFET if its a 'Horiz-Out' type from a very recent donor set....
I see no real issues providing the Donor drive scheme is applied in each case)

All thats needed is to COPY the Design of the Drive Circuit from the Donor set--Schematics for both are needed for this. The last one I converted--was over 25 years ago, but clearly remember it being very easy!

The UK Publication will refer to donor parts from UK sets with specific values of components For those parts, as such would not be suitable for USA engineers, and also worth considering the differences in tuning for the different line frequency between UK and US format sets.....
Stick to Donor parts from what you have around in your country--Follow the drive schematic of the donor--you wont go far wrong!

Really IS a Junk-Parts conversion job, using scrap chassis parts.....

I used a variety of different donor set parts, from Philips G8 and Thorn drive transformers--Whatever I had around actually. I doubt there would be any of these donors around in the US!
Thanks for the info. If that's what it takes to get a near-mint SG-613 Trinitron running reliably, so be it. Looks like I have lots of studying to do.
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  #35  
Old 10-18-2015, 10:57 AM
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Thanks for the info. If that's what it takes to get a near-mint SG-613 Trinitron running reliably, so be it. Looks like I have lots of studying to do.
or, recap, and replace the SG613 with an original, and replace the damper diode with the Sony suggested replacement for reliability. We did this in the 80s to Sonys we serviced, and had only one callback - for an unrelated CRT issue.

Most SG-613's we saw were killed by lightning strikes/surges. A V130LA10A or equivalent across the AC input would likely solve this. Honestly, most Sony's got the 4.7uF treatment - the 4.7uF 160V and the 4.7uF 250V caps would be bad, with high ESR and low value, nearly open. We kept a stock of 4.7uF 250V caps in stock to replace both the 160V and the 250V ones. I've got some 200 or so Sony service bulletins, and those 4.7uF caps are the only recurring parts in the bulletins. Most Sony bulletins are part number changes, so having them comment on any part as suspect makes you realize Sony also knew of the mass failures.
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  #36  
Old 10-18-2015, 02:20 PM
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Last edited by andy; 11-20-2021 at 03:23 PM.
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  #37  
Old 10-18-2015, 04:43 PM
Alastair E Alastair E is offline
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Reading the above suggests the USA versions of these period Sony sets with GCS/GTO's were more reliable than the UK KV1810....

Here, you could meticulously repair an 1810 according to Sony's own service-kit and two weeks later get the set back--All blown out again and with an irate customer to boot! They quickly gained the terrible reputation they have for being near unrepairable. Many places refused to even touch one, even if it wasn't dead.

--The UK sets--Really Were an absolute Abortion, they would blow with no warning and for no apparent reason, no surges, no lightning-strikes, they just died, leaving the customer facing huge bills.

Even Sony UK had issues with them at the time I gather.

--If you're lucky and have a worker--Do as suggested above--Re-cap etc, keep the SG, but if like here in UK you cant get any SG's these days cheaply--Then why not replace and modify--Its Hardly a 'Mutilation' or Major Surgery, merely the substitution of a drive Tx maybe the Drive transistor too, and some passive components, Take you less than half-hour once you thunk it through.....

Does the USA KV1921 set have a SG in both the PSU And in the Line stage, like the KV1810UB British Sony set,--ie, Two of 'em per set....?
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  #38  
Old 10-19-2015, 10:12 AM
dieseljeep dieseljeep is offline
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The British model, probably uses a SG613 in the PSU, because of the 240 volt mains design. Possibly an early SWM design.
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  #39  
Old 10-19-2015, 05:40 PM
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Your KV1810 is prob the same basic set as our KV1710 & or KV1910.
Early ones had 2 Sg613, later ones used 2SC867 in PS IIRC.
Sonys back then could have totally different chassii in the
same model #.
When these sets were new I did a stretch at Sony factory service.
I did smalls & few TV's. Policy was if you didnt find the cause of
a SG fail you changed the whole H/HV/V board. Customers were just
billed $120 labor + an SG & a few small parts total abt $160.
Problem #2 with Sony was they were a super arrogant company.
IF you got to talk to someone they treated you like you just
tracked dog shit into the house. They slowly improved in the '80s.

Nobody in our area would fix one. It was 2 50 mile round trips to Boston
to get one fixed. We refused TONS of them. Even if the symptom
wasnt "dead". After those sets the had a modular set with SG613
which was much more reliable. Then a one board with normal HOT
& an SG for a pin amp IIRC.

73 Zeno


Quote:
Originally Posted by Alastair E View Post
Reading the above suggests the USA versions of these period Sony sets with GCS/GTO's were more reliable than the UK KV1810....

Here, you could meticulously repair an 1810 according to Sony's own service-kit and two weeks later get the set back--All blown out again and with an irate customer to boot! They quickly gained the terrible reputation they have for being near unrepairable. Many places refused to even touch one, even if it wasn't dead.

--The UK sets--Really Were an absolute Abortion, they would blow with no warning and for no apparent reason, no surges, no lightning-strikes, they just died, leaving the customer facing huge bills.

Even Sony UK had issues with them at the time I gather.

--If you're lucky and have a worker--Do as suggested above--Re-cap etc, keep the SG, but if like here in UK you cant get any SG's these days cheaply--Then why not replace and modify--Its Hardly a 'Mutilation' or Major Surgery, merely the substitution of a drive Tx maybe the Drive transistor too, and some passive components, Take you less than half-hour once you thunk it through.....

Does the USA KV1921 set have a SG in both the PSU And in the Line stage, like the KV1810UB British Sony set,--ie, Two of 'em per set....?
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  #40  
Old 10-19-2015, 07:58 PM
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We never turned away a Sony, and actually got the mother lode from other shops that were afraid to touch them.

Sony had a nice set of bulletins you received when you ordered an SG613 from them. The bulletins went through all the pitfalls in replacing the SG613, from testing them, to changing the SID30-15 diode(s) to the upgraded diode. Actually, Andy summed this up in an earlier post.....

What most shops did was instead of ordering a SG613, they popped over to the supply house, bought an ECG276, popped it in, and prayed. No run-through of the suspect stuff that Sony suggested and no upgrade of the damper as suggested. The result was either success or failure - but most often failure.

We junked more Sonys due to bad CRTs (H-K short), mostly the 490BEB22 and the little 370? tubes as well. We had a 12" Sony with no back as a VCR monitor for years - it had no back because it was in a house fire and the back melted. Once removed, it wouldn't go back on, so we kept the set as a shop monitor. As I said in an earlier post, most SG608s and SG613s failed when a power surge occurred during a lightning strike. Most problems were with the 4.7uF caps - Rubycon and Marcons that would fail, and all 160V or 250V types. We replaced all of them with 250V caps - United Chemicons we got from one of the distributors for under a buck each.

I've seen lots of Sony's and the most problematic part ever has to be the MX0841's in the later CRT sets, followed by the caps in the early KVs, and then the STK regulator/audio in the late-80s sets. SG613s were like power supply diodes - understood to be the weak, shorting part in a Sony taking a power hit. 2SC867s and 2SC1034s went too, but the problem was really bad caps in just about all instances I've seen.
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Last edited by Findm-Keepm; 10-19-2015 at 08:03 PM. Reason: MX0841 correction
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  #41  
Old 10-20-2015, 09:05 AM
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Jon A. Jon A. is offline
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Quote:
Originally Posted by Findm-Keepm View Post
or, recap, and replace the SG613 with an original, and replace the damper diode with the Sony suggested replacement for reliability. We did this in the 80s to Sonys we serviced, and had only one callback - for an unrelated CRT issue.
I may as well. At least my SG-613 is still good. Where is the damper diode and what is the sub?
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  #42  
Old 10-20-2015, 09:31 AM
Alastair E Alastair E is offline
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As I recall--The Efficiency-Diode, a metal-cased thing- (In the KV1810) was fitted to a small tag-strip under the heatsink and a large blue film high voltage rated tuning-cap was also attached to it...
--I think the cap was rated at 1,500V as I recall....
Both the Tuning cap--And the diode should be replaced. Its incredible how HOT the blue film cap gets in these sets, and important the cap is a very good quality part, or an original type part....

Failure of either will lead to SG-613, SG-6533 (or whatever its got in there) will suffer....
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  #43  
Old 10-20-2015, 09:55 AM
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Quote:
Originally Posted by Jon A. View Post
I may as well. At least my SG-613 is still good. Where is the damper diode and what is the sub?
The damper hangs off the SG-613, usually on a terminal board, along with two caps - typcially a 330pf and a .014uf to .018uf Blue Epoxy Dipped cap. The blue cap tunes the horizontal to the flyback/deflection circuit, kind of analogous to the safety caps in US made sets. They are obsolete - but a good 715P or 716P (polypropylene film/foil) Orange Drop will also do.

Damper diode part number is SID30-15 on your set - Sony recommends replacement GH3F, Sony Part number 8-719-305-15, also the newer RS3FS diode, Sony Part number 8-719-312-71. ECG/NTE 506's WON"T work. Save your money.

If your SG-613 is good, then I'd recommend finding and replacing all Electrolytics in the Pwr supply and Horizontal - typically on the "VH" board. The 4.7uF 160V and 250V caps cause the most grief.

SG-613 Testing:http://www.talonix.com/images/TestingSG613.pdf
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Last edited by Findm-Keepm; 10-20-2015 at 10:06 AM.
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  #44  
Old 09-26-2016, 12:53 AM
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I finally pulled the back.

This set uses the SCC-121B-B chassis and a 520KB22 CRT. To avoid dismantling nearly the entire set to find out the CRT type I used a bright light and inserted an old car inside mirror glass between the degaussing shield and CRT. Even then it was difficult to get light and mirror positioned just so to read the code.

Last edited by Jon A.; 09-28-2016 at 03:58 PM.
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