Sony Trinitron KV-1921
 

I'll be getting one soon. What I'm wondering most of all is if it's one of those SG-613 sets. Also, is there anything else to watch out for?

SG-613 set or not, I'm stoked to finally be getting another 19" table set.

Anyone?

Well, here it is, arrived yesterday. It runs and the CRT seems strong but the raster shrinks and expands rapidly.

Manufactured September 1977, the same date seen on all those FBI anti-piracy warnings.

Thats either the last SG613 set or just after. I will look it up
tomorrow. Is the pulsating hrz, vert or both ?? Odds are its
just a 'lytic. The last SG613 sets were much more reliable
than the others. In other words the blew them much less often.
The rest of the set is quite reliable.

73 Zeno:smoke:

Good to know, and thanks in advance. The pulsating is horizontal and vertical.

That's one pretty TV set. I remember that style when they were new. Liked them in high school, like them now.

Be sure you are dealing with an SCC100 chassis first.
Sets is SG613. Uses a short lived modular chassis
thats very nice. Pulsing probably a cap in the PS but
some voltages need to be checked. DO NOT slip
on this set or you will loose the SG613 & other stuff.

73 Zeno:smoke:

Crap. I'll just leave it unplugged until I can dig into it.

I think I heard there are mods that make these things more reliable and allow them to use more common transistors.

I used to have one just like that from '79. It had varactor push button tuning. It worked, but the high voltage had a really weird problem.

I have one of these with the push button channels. Made in 1979.

It's actually a really fantastic watch.

Be sure to let Sony know if you do find that mod - Sony never issued any kind of mod in the SG-613 or SG-608 sets. It's a robust design, made weak by bad solder, bad caps and lightning strikes that juice the sets.

I'll see if I have the original service manual still - most of these sets were a cap swap (4.7uF@160V and 250V - we kept them in stock...), a bad chroma chip CX1-something, or a bad solder connection in the sweep area (which led to the 608/613 failing), and the occasional open cathode in the CRT, 490BEBP22 in most of the 19"ers.

Even in the 90s, the SG-613 from Sony was about 7 or 8 bux, far cheaper than a 6LQ6 was for tube sets. Most problems occurred when folks went with just the SCS and didn't look further, like the damper diode (SID30-15, subbed by Sony to another number - I can look it up) or the bad solder. You could power one up, check for proper drive, and know if you had it fixed before installing the SG-613. I think I've posted the Sony Bulletin on how to properly check the SCS out of circuit..

I remember the dampers opening up. Had a top hat style
wrapped in metal holder, new one was modern type.
When I worked at Sony SG613, some clocks, video
heads & a few other things were tracked. Seems at some
FSC's they were getting stolen. And the SG613 had
NO warranty, if a regular shop blew one they ate it.

73 Zeno:smoke:

I thought I heard a passing mention of a SG-613 mod on here somewhere, but who knows. I read so much here it kind of runs together.

I got that series of Japanese TV service manuals and only left out the one for Sony, thinking I'd never take on another one, who'd 'a thunk it. I'll just have to be extra cautious with this one and try to lay my hands on extra SG-613s. They should turn up all the time considering how sets that use them ate them so often.

I assume these were known for purity issues as well. I forgot to mention the image is darker at the top left, just like on my decade-newer KV-1926R.

A ure sign there is a bad cap - shading of the left hand side of the screen is a common B+ filter problem with Sonys.

Check the ESR on all the caps in the B+, vertical (save the 2SC867 or 2SC1034!!) and the horizontal sweep, and you'll likely fill a mug with bad caps. Sony used good caps, it's just age that kills them - they've met their 5,000 hour service life.

Even after getting a set running, we'd run through the caps, replacing any marginal caps. Nothing worse than a call back for one stinkin' cap...

Best source of SG613 is junk sets. They either work or not,
dead shorted or OK.
Semis have an infant mortality. If it lasts a few minutes
its life expectancy jumps to near 100% for decades. So
if you got a Sony with a bad jug pull the SG613's &
? 2SC867's ? was it ? They are as good as new IMHO.
As long as you get any kind of raster they are fine.....

73 Zeno:smoke:

The caps probably went bad from lack of use. If I recall correctly, the fellow who gave me this set said it hadn't been used in about 20 years.