27" RCA tv chassis:CTC187 subbing HOT

[Sidney]

27" RCA stereo tv model:F27676BC,chassis:CTC187AJ,year:July 97.
The customer spilled water and since the tv has insufficient
horizontal deflection specially on the left side (almost half of the
screen) so I entered EEPROM service mode but changing parameters made
no difference after troublshooting with my ohm meter (Fluke DMM series
II model:29) I discovered that Q4401=2SD1878=RCA # 191142=NTE2331 has
a base to emitter resistance of 50 ohms so I would like to know if
that's the normal resistance as according to NTE it does not have a
base-emitter resistor.
As I have learned the hard way that some HOTs are designed to have
that low b-e resistance value like the HOTs used in CTC203s:

Q14401=2SD2758=242224=b-e is 70 ohms
Q14401=NTE2353=b-e is 40 ohms

again even though the NTE website or paperback cross reference books
don't show a resistor.

Second question if HOT=2SD1878 is not supposed to have a low b-e of 50
ohms but instead 600+ ohms then can I sub it with the
HOT=Q4401=BUH517=RCA # 223942=NTE2637 used in the 31" RCA
chassis:CTC187?.Thanks in advance.

Sidney
E-mail:[email protected]
Dartmouth,Nova Scotia
Canada

 

[Rono]

The low resistance is the internal damper diode!
That's ok! Check high voltage caps in the horizontal
pincushion circuitry, also, look for "the spilt" fluid under
components! Also check the diodes, & capacitors in the
pincushion circuitry! Rono.

 

[[email protected]]

Actually 27" RCA units also use that BUH517:

27" Proscan tv modelS27108FX3,chassis:CTC187BF2 BM,year:Nov
1997,Q4401F=BUH517=RCA # 223942=NTE # NTE2637
so can I use a BUH517?.

Sidney
Dartmouth,Nova Scotia
Canada

 

[RonKZ650]

Subject: Re: 27" RCA tv chassis:CTC187 subbing HOT

From: [email protected]
Date: 11/23/04 8:56 PM Mountain Standard Time
Message-id: <[email protected]>

Actually 27" RCA units also use that BUH517:

27" Proscan tv modelS27108FX3,chassis:CTC187BF2 BM,year:Nov
1997,Q4401F=BUH517=RCA # 223942=NTE # NTE2637
so can I use a BUH517?.

You can try it. If it runs real hot you'll know you can't use it, and you can
see if the width problem disappears, which I'd personally say less than a 0.1%
chance. The 2SD1878 does have a damper diode in it so you're barking up the
wrong tree replacing it. Leave it alone and go on. I'm at a loss why RCA used
10 different outputs in the 175-187 series, but they did, and it seems it's
important to stay with the right part or overheating will result. A NTE will
overheat, I'll guarantee that much.
Ron