Sony KV-27TS29 Power Supply

[Chris F.]

I bought this nice set from a guy who used to work in an electronics shop.
He obviously gave it a going-over, nothing appears messed up but he did
leave three transistors missing: Q601, Q602, and the horizontal output
transistor. The first two are located side-by-side on a heatsink, on the
primary side of the switching power supply. Testing of the flyback indicates
an internal short - probably the original cause of the set's failure.
If anyone could tell me the numbers of these transistors (or provide me
with a scan of the schematic) I'd be very grateful.
Thanks.

 

[Rono]

Q 601, & 602 are 2SC4834, the horizontal output is 2SD4927,
I believe, replace VDR601-603 also, Sony Sp-Kit, has these
parts but VDR's are seperate! 1.0 ohm fusible is also bad! Solder
all around the horizontal drive circuitry, replace electrolytic capacitor
by the drive transformer, if this unit has one! Rono.

 

[Don]

Hi,

Q 601, & 602 are 2SC4834, the horizontal output is 2SD4927,

This sounds much like a KV32S22 I'm tinkering with
("dead", no picture, no stdby code, etc.) -- though I would
have to check the P/N of the HOT to be sure.

I believe, replace VDR601-603 also, Sony Sp-Kit, has these

Hmmm... I only see *one* VDR in this set ("G" board).
What does this "kit" include -- just the 2 chopper Q's plus HOT?
How/where can it be purchased? (any idea of cost?)

parts but VDR's are seperate! 1.0 ohm fusible is also bad! Solder

Yes, I see R607 (0.1ohm) is open.

all around the horizontal drive circuitry, replace electrolytic capacitor
by the drive transformer, if this unit has one! Rono.

Hmmm... several electrolytics in proximity to the HDT. A small 0.47uF
in series with the base of the HDrive transistor, perhaps?

I suspect I should also check the flyback? Or, is all this just
a colossal waste of time (and money!) -- maybe just toss the set?
(seems that everyone I know who has owned a Sony TV has
had it die in 4 - 6 years)

Thanks for any insights!
--don

 

[Rono]

Don, the kit has 2- 2SC4834, the 2SD4927, & the 0.1 ohm fusible
resistor! $ 12.00 approx. Canadian! There may be only one VDR
in the unit, but i doubt it! VDR601 # 1-807-288-11, and VDR602 & 603 #
1-810-973-21!!
Flyback is likely good! The drive capacitor by the horizontal drive
transformer has to be polarized (electrolytic), in order for it needing
to be replaced! Sony is definetly worth repair, as long as the CRT is
good! The best T.V. around in my opinion! Below is the company I
usually get parts from! Good luck, Rono.

www.globalsemi.com
Ther'e in Mississauga, Ontario 1-800-668-8776

 

[Chris F.]

I tested the flyback by means of a homemade flyback tester, as described in
the S.E.R FAQ. Flyback produced almost no output at all when connected to
the rig. Also, I noticed a faint odor of burnt epoxy (a smell very common to
Sony flybacks!), so I'm 99% certain that the flyback is bad at this point.
Thanks for the info, if I can get the PS to start up, I might order a
flyback and see what happens. Flyback retails for about $40 Cdn....

 

[Jason D.]

I tested the flyback by means of a homemade flyback tester, as described in
the S.E.R FAQ. Flyback produced almost no output at all when connected to
the rig. Also, I noticed a faint odor of burnt epoxy (a smell very common to
Sony flybacks!), so I'm 99% certain that the flyback is bad at this point.
Thanks for the info, if I can get the PS to start up, I might order a
flyback and see what happens. Flyback retails for about $40 Cdn....

Not recommanded. Get Sony flyback but rest of parts is not a problem,
Most Sony flybacks is usually about 80 to 120. 40 is generic and will
not do 100% properly.

Global does sell Sony parts, get the flyback for that, part number is
on your old flyback's sticker.

Also, the solder job must be done on whole horizontal section, part of
SMPS and part of vertical circuits.

TS series is typical Sony stuff.

Cheers,

Wizard

 

[Don]

Hi,

Don, the kit has 2- 2SC4834, the 2SD4927, & the 0.1 ohm fusible

My HOT is 2SC5148 (8-729-035-75). Are there different "kits"?

resistor! $ 12.00 approx. Canadian! There may be only one VDR
in the unit, but i doubt it! VDR601 # 1-807-288-11, and VDR602 & 603 #
1-810-973-21!!

I doubled checked the schematic and only one VDR (KV-32S22 G board).
Sony P/N 1-610-974-21 at VDR601

Flyback is likely good! The drive capacitor by the horizontal drive
transformer has to be polarized (electrolytic), in order for it needing

I'm not sure which cap you mean... I have C502 (0.47uF 50V) at
the base of the horizontal drive transistor (which drives the
horiz drive xformer which drives the HOT).

to be replaced! Sony is definetly worth repair, as long as the CRT is
good! The best T.V. around in my opinion!

What typically *causes* this sort of failure (Q601/602)?
I would have assumed the flyback died which would take
out the HOT (I still haven't check my HOT) and, eventually,
the chopper driving everything (via 601/602)

Below is the company I usually get parts from! Good luck, Rono.

www.globalsemi.com
Ther'e in Mississauga, Ontario 1-800-668-8776

Thanks, I will check them out.
--don

 

[Jason D.]

Hi,



My HOT is 2SC5148 (8-729-035-75). Are there different "kits"?

What is your original HOT? Has to be same.

I doubled checked the schematic and only one VDR (KV-32S22 G board).
Sony P/N 1-610-974-21 at VDR601


I'm not sure which cap you mean... I have C502 (0.47uF 50V) at
the base of the horizontal drive transistor (which drives the
horiz drive xformer which drives the HOT).

That's true but in Sony, it is very common for bad solder joints in
horizontal circuit to blow the horizontal transistor, that includes
the horizontal transformer driver because this is part of whole
horizontal circuit.

What typically *causes* this sort of failure (Q601/602)?
I would have assumed the flyback died which would take
out the HOT (I still haven't check my HOT) and, eventually,
the chopper driving everything (via 601/602)


Thanks, I will check them out.
--don

Cheers,

Wizard

 

[Don]

What is your original HOT? Has to be same.

As I said, 2SC5148 -- per the schematic/parts list (I haven't yet
examined the device itself). But, the kit previously mentioned
does not appear to use the same HOT (though Q601/602. are
2SC4834M in my parts list and R607 is 0R1 fusible)

That's true but in Sony, it is very common for bad solder joints in
horizontal circuit to blow the horizontal transistor, that includes

blow the HOT? Or, the horizontal *drive* transistor?

the horizontal transformer driver because this is part of whole
horizontal circuit.

OK. The bad solder joints are a "quality" issue? Or, just fatigue
from years of use (temperature cycling, etc.)?

Thanks!
--don