zenith t.v. model # pv4655lk9

CTORO wrote in news: snipped-for-privacy@news.diybanter.com:

I am working on a different zenith with same symptoms. There is a solder in, 2 amp fuse that feeds dc to the HV/horizontal section. Mine is blown, and blows immediately when I replace it.

An online database says I should replace the flyback. If the fuse were not blown, there are a couple of solder connections and a diode, and a capacitor that they recommend replacing.

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

It has sound with no horizontal output? That's rare...

Tom

Tom MacIntyre wrote in news: snipped-for-privacy@4ax.com:

Why am I so lucky as to get the 'rare ones'?

1993 Zenith TV. model number SL3585BT (zenith C8 Chassis) Serial Number 381-34431174 Blows FX3403 (2A) fuse in HV / horizontal circuit. I do not have a schematic. None are available [so zenith says]. the board has the number 204-2755-09 on the edge. Suggests 'replace flyback transformer' I am looking for replacement flyback or an exchange on the entire board.

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Have you checked the horizontal output transistor? Andy Cuffe

snipped-for-privacy@psu.edu

Andy Cuffe wrote in news: snipped-for-privacy@4ax.com:

Not yet. Any idea where / which one it is? No schematic.

I have been poking around with a curve tracer and haven't found any obvious problems.

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bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Whoa, wait a minute. You are poking around a tv set and cannot identify the horizontal output transistor?

Please pick up any book on tv repair (post 1985) and do a good quick reading before you go any further. People here can help, if you have some basic understanding of what you are looking at inside the tv set.

might also be of some use. I am sure any community college library that offers vocational electronics will have one available.

The module number that is on the board starts with a 009-xxxxx-xx number and is usually on a label somewhere near the system controller ic. In case you cannot find the module number, download z-tips here:

and look up the model number. There may even be some specific tips for that chassis.

It might be cost/time effective to send the module out to PTS for them to repair it. At least check on the price. Sometimes on the older Zenith modules with limited parts availability, they are the least troublesome way to get the tv repaired.

One thing that comes to mind is the pin and horizontal shaping coils, as I remember one of those commonly goes bad in that set and takes out several other parts.

" snipped-for-privacy@locl.net" wrote in news: snipped-for-privacy@g43g2000cwa.googlegroups.com:

Being able to 'guess' which one it is and knowing are two different things.

I have 'some idea' of the basics, Texas Electronics Association Certified Electronic Technican #TEX-173 in audio, radio-TV and industrial electronics. I used to have an fcc 1st phone and 2nd telegraph license w/ radar endorsement. I owned a shop in Texas in the early 70s. TVs have changed a bit since I was working on them every day.

I will check.

Will look again.

Some interesting information: C8 chassis service manual CM-145

9-1270-02 HOR/VERT Sweep & SMPS

a few. No pictures so far.

C8-L series [no idea which series I have, yet]

location TX3204 (95-4134-09) REPLACE FLYBACK WITH PART# 95-4134-11. PARTS INFORMATION SHOWS REPLACEMENT TO BE A -10. THIS IS WRONG.

The set was working normally one moment and the picture disappeared. Sound still ok. No HV, no raster, the 2 amp fuse blown. Replacement blows immediately.

Thanks for the info.

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bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Take the TV to a shop and get an estimate before you kill yourself.

It definitely shows that you don't have a clue as to what you are doing.

jmo kip

"kip" wrote in news:newscache$8qyfki$83i$1 @newsfeed.niagara.com:

Have you ever taken a 48 inch tv anywhere? Last time I tried to move the thing, with three helpers, it almost killed us.

I taught basic electronics, Radio TV repair, and Avionics in the early 70s.

Top posting your comments shows you don't know how to use usenet. You also missed my 05:54 reply to dkuhajda, which would have set your mind at rest as to my killing myself.

[quote] I have 'some idea' of the basics, Texas Electronics Association Certified Electronic Technican #TEX-173 in audio, radio-TV and industrial electronics. I used to have an fcc 1st phone and 2nd telegraph license w/ radar endorsement. I owned a shop in Texas in the early 70s. TVs have changed a bit since I was working on them every day. [unquote]

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Yes I move Pro Sets every week Thats My Job... Call somebody in for an estimate of costs...Then you will know.

"kip" wrote in news:newscache$qa3gki$ddi$1 @newsfeed.niagara.com:

Thank you for your advice.

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

" snipped-for-privacy@locl.net" wrote in news: snipped-for-privacy@g43g2000cwa.googlegroups.com:

My first guess is QX3208, but, as I said, I don't have a schematic.

I am 'poking around' with a simple curve tracer that applies an ac voltage across the device under question. One axis on the scope shows the voltage across the device, the other shows the current through it [as sensed across a series resistor]. I built it from an article in a radio tv mag back in the early 70s. I used it for a lot of trouble shooting when I was fixing radar and other equipment on ships and boats on the mississippi in the mid

70s and later when I was doing board repair on minicomputer and instruments in the late 70s. Often you can test 'in circuit' with it. Sometimes, when a low resistance/inductance or high capacitance is in the circuit, you need to cut traces or unsolder stuff.

Anyway, That is what I am using to troubleshoot the chassis, which I have pulled out of the TV.

The only such number I see is on a paper tag on the OTHER board.

9-1235-2

That board has the tuners and controller stuff. I haven't looked at it carfully.

It sould SURE help to have a road map, layout and schematic. Surely someone has such for the zenith C8 chassis.

I have fixed many things without schematics, but I hate it.

--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Since your experience is pre-1985 you are probably use to working with a separate high voltage output tube and/or a horizontal output tube. You should know what a flyback is even from that experience.

Most tv sets from the early 1980s up to but not including the tv sets that use high scan technology, HDTV, use a common horizontal output transistor to generate the horizontal sweep and the high voltage through the flyback. You should be able to identify it by finding the larger transistor (as it needs to pass a lot of current 1.0 amps and some rf and the horizontal sweep) that is on a heatsink near the flyback. In fact the collector of the transistor will be directly connected to one pin of the flyback.

I think Sams photofacts lists most all Zenith models and chassis:

You can also see if your local library in your nearest large city has those in the reference section. Many libraries do have Sams subscriptions and you can photocopy the sections you need.

FYI the horizontal output transistor need only be checked C-E junction. They cannot be checked normally all the way around as there is an internal 40 ohm resistor between the B-E junction.

" snipped-for-privacy@locl.net" wrote in news: snipped-for-privacy@z14g2000cwz.googlegroups.com:

We had both tube and transistor TVs back in the 70s.

Both solid state HV Rectifiers and Vacuum Tube HV rectifiers.

The HV was rectified from the flyback transformer. No separate supplies in any TV I have ever seen, including some old, round CRT, B/W TV's I salvaged as a kid, collecting parts.

Certainly. They are hard to miss. They kind of 'reach out and grab your attention'. :)

There are several.

Good hint.

They didn't list the model number SL3585BT. I asked.

They may have the zenith C8 Chassis.

I live in Baton Rouge, LA.

I even called zenith. When I got past their 'we only sell to technicians', I got 'that manual is no longer available'.

THAT is important to know. Thanks. I would have said 'bad transistor'.

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bz    	73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+ser@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Sorry...a 1993 TV with no H output should not have audio.

Tom

Tom MacIntyre wrote in news: snipped-for-privacy@4ax.com:

Apparently this set doesn't know the rule.

lists 'has audio, no raster, no HV' as one of the possible symptoms.

The set has three different fuses. The one that is blowing IS NOT the main fuse.

Do you have the Zenith C8 Chassis schematic and or roadmap?

--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

Since that set was a module level repair under warranty and the module cost up until recently was low enough that component level repair would cost more in time and effort for the big failure, many shops simply did not bother with the full service manual/schematic set.

The H.W.Sams reference should come up with the CM-145 chassis designation. Realize that it might not be 100% exact as Zenith would use the basic same chassis and make some changes for specific models.

should be able to get you a repaired module. They also have a tech tip section and on the C8 chassis it indicates that the picture tube should be checked as a G1 short can damage the power supply. In every case of the horizontal output transistor B+ fuse going open with a good flyback and shaping coils wound up being a bad picture tube, in the 32" and 35" Zeniths.

The big picture tube failures Zenith had was the 25" and 27" size tubes, but I did see a few (less than 5) on the larger tube sizes. It might be beneficial to get a hold of a good recent crt tester and verify the picture tube before spending too much time on the set.

" snipped-for-privacy@locl.net" wrote in news:1122862749.552123.98480 @z14g2000cwz.googlegroups.com:

Found several C8 chassis under cm145. I just ordered the microfisch for A and C. Hope that will be close enough. Will have to scan the fisch when I get it so I can read the thing. Oh well. Cheaper than paper. Too bad they don't have on line for download.

:) or too much money. I doubt it is worth replacing the Picture tube.

Sounds like good advice. I thank you!

A G1 short should show up with an ohm meter check, shouldn't it?

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bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an 
infinite set.

bz+sp@ch100-5.chem.lsu.edu   remove ch100-5 to avoid spam trap

I saw a Philips that would do the same also, some years back.

Generally, though, TV's have most supplies derived from the H scan...no H, no power. Even those with switching supplies usually will not have power when the horizontal is out.

Tom

Tom