[TechAssist] Another CTC187CN3 regulator and HOT running hot
- From: Gary McCartney <gary@xxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Sat, 14 Aug 2004 03:03:01 -0400
I have a 31" GE TV with chassis CTC187CN3. Set came in with regulator,
HOT, CR4106 and fuse all bad.
I used a generic STK730-150 (same as # on original) and an OEM 223942
(BUH517) for the HOT. For the CR4106, I used a generic MR856, which has
faster switching time than the original PFR856.
Fired set up and it ran but after an hour the HOT heatsink was at 60
deg. C and the reg. heatsink was at 70 deg. C. B+ on cathode of CR4106
is 146V with set off and 139.2V with set on.
Since then, I have changed the following parts, all OEM unless otherwise
noted:
- 215541 hor driver transformer
- 188594 cap, C4306
- 175374 22 ohm resistor , R4402
- 214753 cap, C4403
- 206008 cap, C4402
- 242907 CR4402 damper
- 176296 CR4303 diode
- 218492 cap, C4407
- CR4403 - used MR856 as sub to PFR856 164589
- C4105 cap 10 uF 200V generic
- C4709 47uF 35V generic
- R4126 30K 3W resistor generic
- CR4109 7.5V 1W zener diode generic
also checked C4107 for ESR and value, checked ok. Tried a 2SD1886 for
the HOT as well as a second OEM 223942 BUH517, from the same lot as
first one. No temp differences except the 2SD1886 ran hotter if anything.
With all these parts changed, I see very little improvement if any in
the heat situation. The picture looks absolutely fine, no bowing,
shrinkage, or anything.
I added extra heatsinks to the REG. and HOT. This has brought the REG
temp down to 60 deg. C and the HOT temp down to 40 deg. C. I'd still
like to know what can be causing these temperature problems. I'm sure
I've had CTC187's in here that ran much cooler than this. A few months
ago I had another one running hot. Had same problems trying to cool it
down so I installed heatsinks. Brought the temp down just like this set
and I've never heard back from the customer.
Any ideas to suggest? an OEM STK730-150 is way too expensive but is that
the answer? I asked other members who buy from my supplier (Global) if
they used those generic STK's and they all said "all the time, no
problem" What about the HOT heat? Flyback? Maybe but that other set I
had, I did replace the flyback and it still had the same problem as this
set.
Thanks for any help. Sorry the message so long.
Gary McCartney
McCartney Electronics
Guelph Ontario Canada
Est. 1984
email: gary (at) number63.ca
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