[TechAssist] Re: RCA CTC197CA
- From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Tue, 26 Nov 2002 09:35:29 -0600
First, I have seen many IHVTs that ring "good" and are in fact bad.
When you say it is still not regulating what do you mean? This power supply
may run as high as 165vdc in standby. I am told that 130-160 is ok in
standby, but it should regulate when running.
Here are some of my notes followed by a previous post:
IHVT 237506 2 good units measured.
Pins 2-3 ring 57, 54 on the z-meter. Measures 2.77, 2.85 mH
Pins 1-2 ring 29, 25 and measures 1.49, 1.43 uH
Pins 1-3 ring 57, 54 and measures 2.52, 2.64 mH
Pins 6-10 ring 48, 41 and measures 530, 540 uH
On the TVA
Pins 1-3 ring 30, 31
Pins 1-2 ring 14, 16
Pins 2-3 ring 30, 32
Pins 6-10 ring 36, 36
Pin 5-anode leaks 2 mA
BAD UNITs z-meter
pins 2-3 ring 19, 40
pins 1-2 ring 2, 17
pins 1-3 ring 18, 39
pins 6-10 ring 7, 30
On the TVA
Pins 2-3 ring 15, 27
Pins 1-2 ring 0, 11
Pins 1-3 ring 14, 26
Pins 6-10 ring 0, 26
Don't cheat on the parts:
r14107 244214 43ohms
r14109 179317 1/4w 750ohms 5%
r14108 244215 .1ohm 3W
q14101 244223
q14102 147665
q14103 232218
q14106 215495 smd, maybe bad
q14107 215495 smd, maybe bad
q14108 215496
u14101 223653
u14102 231525
The failure was probably caused by u14102. This is a precision reference
IC. Although the opto-isolator is probably good for the buck it costs it
isn't worth the gamble. Also, very carefully check all of the pins on the
switchmode transformer, ensuring that the traces are good.
This power supply needs about 80vac to run. It is a frequency modulated
regulator.
Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl. 32506-3310
850-456-5995 voice
850-458-6369 fax
Mailto:Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com
Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, FL 32506-3310
850-456-5995 voice
850-458-6369 fax
Wayne@xxxxxxxxxxxxxxxxxxxxx
www.PensacolaTVRepair.Com
----- Original Message -----
From: "Jim & Sharyn" <sandman@xxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, November 26, 2002 9:25 AM
Subject: [TechAssist] RCA CTC197CA
>
> I have a CTC197CA in a 35". Came in with a shorted HOT (Q14401). B+ was
not
> regulated so I changed Q14101 an d U14101 in the power supply also R41125
> open. Now still no B+ regulation...clicks 3 times then shutdown. Checked
> over the remaining components in the supply and the flyback rings good. If
> anyone has any tips for this chassis they would be appreciated. First
CTC197
> I've seen and have no data on it.
>
> Thanks
> Jim
> Maxfield Electronics
> Northfield, NH USA
> sandman@xxxxxxxxxxxxx
> 603-286-2454
> 603-286-8062 Fax
>
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