fixing my TV - & parts?
DurrElec
dealers in the USA stock the ECG line of generic replacement parts.
Robert McPherson durr...@aol.com Voice (502) 367-9324 Fax (502)
367-7107
Ray Decoteau
cfie...@nmsu.edu writes:
>I need to get a replacement transistor for the horizontal output, it is
a
>2SD1555 according to the schematic and the transistor itself is marked
>with D1555 and has a logo tha looks like a "T"
>
>The distributers we use don't seem to have this part so I wonder where I
>might be able to order one.
The transistor is available at MCM Electronics (1-800-543-4330)
~Ray
Charles A. Fielder
2SD1555 according to the schematic and the transistor itself is marked
with D1555 and has a logo tha looks like a "T"
The distributers we use don't seem to have this part so I wonder where I
might be able to order one.
I found it attatched to a very large heat sink with some white substance
- I'm assuming that it is just a regular old thermal putty. Is this
assumption correct? It seemed that it was pretty thick on there - I
remember learning that putting too much thermal grease was as bad or
worse than using no thermal grease.
I checked the horizontal drive transistor and It didn't have any shorts
accross the junctions - is there anything else I should check?
Thanks in advance...and thanks to Sam Goldwasser for his very informative
FAQ and EXTENSIVE web page!!!
--
Charles Fielder
cfie...@nmsu.edu
Gregg Lansley
writes:
Your distributor should carry either the Philips ECG or the Thomson
(RCA) SK line of replacement semiconductors. The 2sd1555 is a very
common horizontal output transistor with a plastic back and is
replaceable with either an ECG2331 or an SK9422. Many aftermarket
suppliers such as MCM (1-800-543-4330) carry the 2sd1555. MCMs price
is $4.29.
The white substance is silicone heat sink grease. It's available just
about any place. Try Radio Shack (p/n 276-1372, $1.69 for 6.5 oz).
As to why it blew; sometimes it just happens, sometimes the flyback
transformer is shorted. Guess you'll just have to replace the
transistor and see. If you have a Variac, plug the set into it and set
it for about 85-90 volts. If the set works properly, gradually
increase the voltage.
Jc Lachapelle
output,
CAF> 2SD1555. - is there anything else I should check?
ECG2331 is listed as a replacement for 2SD1555. Specs of ECG2331:
NPN + Damper, 800 Vce, 1500 Vceo, 6 Amps, 120 Watts, .1 uS
If you have other Horiz.Out/Damper transistors to "spare" on hand,
(D1650, D1879, D2089, D2095, D2125, etc) and "feel lucky", try one...
I often use the BU508D (D is for integrated Damper Diode inside) as
replacement for many Horiz Out transistors (1500Vceo,700Vce,8Amp).
First and most important, carefully observe all safety guidelines:
Check all voltage lines and their rectifiers supplied by the flyback
for shorts; check B+ for proper voltage (regulator operation);
check for open or shorted condensers in flyback circuit.
Put a series resistor (about 200 Ohms, about 20 Watts; or a few 120 V
lightbulbs: 40 W, 60 W, 100 W, etc) in B+ line to flyback/Horiz for
current limitting before turning power on for the first time. Test
and check for Horiz Out transistor overheating; If ok, lower
resistor
value, test again; if ok, lower resistor value, test again; etc...
If you have a variac, use it also...
This method saves many transistors for me...
--
| InterNet: Jc.Lac...@micronet.mba.org
| Standard disclaimer: The views of this user are strictly their own.
Sam Goldwasser
> I need to get a replacement transistor for the horizontal output, it is a
> 2SD1555 according to the schematic and the transistor itself is marked
> with D1555 and has a logo tha looks like a "T"
How did it fail? Did the TV just not power up and perhaps blow a fuse?
Or were there preliminary symptoms which would indicate that it was blown
by the failure of another part?
> The distributers we use don't seem to have this part so I wonder where I
> might be able to order one.
The places listed below should have it.
> I found it attatched to a very large heat sink with some white substance
> - I'm assuming that it is just a regular old thermal putty. Is this
> assumption correct? It seemed that it was pretty thick on there - I
> remember learning that putting too much thermal grease was as bad or
> worse than using no thermal grease.
Exactly. You probably have enough extra to last a lifetime and too thick
a layer hurts thermal conductivity perhaps shortening the life of the
previous transistor. You want just enough to fill the voids.
> I checked the horizontal drive transistor and It didn't have any shorts
> accross the junctions - is there anything else I should check?
Also, before you order, check the fusable resistors in the HOT circuit -
one of these may have blown when the transistor went poof. If you have
the equipment, check the caps around the HOT and the flyback transformer.
> Thanks in advance...and thanks to Sam Goldwasser for his very informative
> FAQ and EXTENSIVE web page!!!
There is always the possibility that the transistor was caused to fail
by a problem with some other part. When you get the new one (maybe get
two as insurance) power the TV through a 100 W lightbulb. If it appears to
operate more or less normally (there will probably be some reduction in
picture size, maybe some hum, etc.) then remove the lightbulb. If there
is anything grossly wrong or the lightbulb just glows at close to full
brightness, then there are other problems.
--- sam
> Charles Fielder
> cfie...@nmsu.edu
The following are good sources for consumer electronics replacement parts,
especially for VCRs, TVs, and other audio and video equipment:
MCM Electronics (VCR parts, Japanese semiconductors,
1-800-543-4330. tools, test equipment, audio, consumer
electronics including microwave oven parts
and electric range elements, etc.)
Dalbani (Excellent Japanese semiconductor source,
1-800-325-2264. VCR parts, other consumer electronics,)
Premium Parts (Very complete VCR parts, some tools, adapter
1-800-558-9572. cables, other replacement parts.)
Computer Component Source (Mostly computer monitor replacement parts,
1-800-356-1227. also, some electronic components including
semiconductors.)
Dave Mcdonald
>
>In article <3qjcup$9...@bubba.NMSU.Edu> cfie...@nmsu.edu (Charles A. Fielder) writes:
>
>> I need to get a replacement transistor for the horizontal output, it is a
>> 2SD1555 according to the schematic and the transistor itself is marked
>> with D1555 and has a logo tha looks like a "T"
>
The 2SD1555 can be replaced with a Philips ECG 2331, or a 2SD1556.
The original part was made by Toshiba, hence the "T"
These transistors fail regularly. The 1555 is a 5 amp junction, and the 1556 is a
6 amp junction. Keep in mind that these devices have an internal damper diode and
will measure a SHORT arcoss the E-B and C-B junctions. This is normal. If you have a
good DMM like a Fluke, you will notice that it is not a true short, but very close
ot. It will measure 0.03 volts drop. A standard transistio has about a 0.6 volt drop
across the junctions. (Silicon type)
The point is many a technician has been fooled by the unusually low readings that
these transistors give. I have 2 tech at work that are constantly changing them, only
to fond that they problem is still there. That's when they call me in, and I embarase
them by installing the original again, and finding the true cause.
If the transistor is indeed "kahoofed" check the connections at the horizontal
drive transformer, as if drive is lost during set operation it will usually take out
the output faster than you can blink.