Black & White TV Parts / Deflection Yolk

belairjo · Feb 25, 2009

G'Day All at VCF,

Please forgive me for looking around in here for a vintage electronic part from a 1973 Multi-Channel Analyser. An MCA is an electronic unit that utiltises a CRT, apparently the components operate similarly to a black & white TV.

We lost the operation of the monitor after a power surge.

We have tested the circuitry of the unit and replaced a diode.
The defelction Yoke part is presumed faulty. There is one hair-thin wire from the yoke loose. The yoke was available from US partstore however is no longer available www.partstore.com/Part/Matsushita/Panasonic/K905N9/Matsushita/Panasonic/TLY80339A/New.aspx

Part and Unit details:
The original part # is Panasonic TLY80339A .
Unit Make & Model# Matsushita M-9004NA .
Model # of the CRT: 240AKB4(N) Chassis family # FA3520248

Please see Pics attached

Any Help will be very much appreciated.
THANK YOU THANK YOU THANK YOU

channelmaniac · Feb 25, 2009

What's the video input on that monitor? TTL or composite? How bit is the monitor in inches (measure it diagonally)?

I have an old B&W monitor tube & boardset and if you can use it you're more than welcome to it for shipping costs. I dunno how easy it is to ship a bare CRT tube to down under though.

RJ

belairjo · Feb 26, 2009

RJ
The input is TTL. The monitor is 9 inches.
Do you have the model numbers of the tube and boardset at all?
Thanks
Jo

channelmaniac · Feb 27, 2009

The chassis is labeled Motorola Display Systems, but the paper tag that was on it showing the model is long gone.

I'll go out to the garage later and get the model # of the tube. I think it's 9" diagonally.

Sorry for the delay in replying. There was a reorg at work this week and I'm scrambling trying to figure out what's going on with my new position.

RJ

patscc · Feb 27, 2009

yoke

yoke

Hey, guys. What's the resistance on the yoke coils ? There should be two coils, horizontal and vertical (if it's the box from earlier).
If the vertical coil is open, you'll get a horizontal line. If the horizontal coil is open, you'll probably get a vertical line. If both are open, you might get a dot.

Do you see the heater glowing in the neck of the CRT ?
You can repair yokes, if you can see both ends of the wire. You can splice them together, bear in mind that the wire is enamel-coated, so you need to sand the ends of them & flux them before you add a bit of solder for the join.
patscc

chuckcmagee · Feb 27, 2009

Indeed, I had a H89 that was super poorly packed. The yoke ended up slamming around. The metal cut the windings, at least in 3 places. I never was able to find all the ends from the cut.

belairjo · Mar 2, 2009

Resistance

Resistance

Hey guys, Thanks heaps for your assistance, much appreciated.

Btw the Red and Blue wires: no reading

Btw the Yellow and Grey wires: no reading

The DC resistance at the deflection yoke is 1.9MΩ btw the inside wires (Blue/ Grey) and 1.9MΩ btw the outside (Yellow/ red).

No registration btw Red/ Grey.

We are getting the 1.9MΩ at the power input side to the yoke.

If we could get an idea where the loose magnet wire goes to - we could be in business - but it seems like the yoke is dead.

We are trying to find someone who may have a NOS supply of this part.

It's vintage alright!... A vintage electronic supplier - Moyer are looking for us.

If anyone else can suggest other vintage suppliers throughout the world - maybe even Japan as this is where the unit was originally made.

Kindest Regards
Jo

patscc · Mar 2, 2009

dead yoke

dead yoke

Yah, the yoke is dead.
Or, you could be unlucky and just have a non-resettable thermal fuse that opened up in both windings.
Odd for both windings to go.
Can you post some closeups of the yoke, and maybe someone can figure out where the hanging wire goes to ?
While you're at it, can you post (or repost, if you already posted it) the make/model of the tube, in case anyone has a comparable tube they can nick the yoke from ?
patscc

belairjo · Mar 2, 2009

More Resistance Values

More Resistance Values

Hey Guys, we just pulled the yoke out again and tested out of the circuit - now we are getting:

Inside wires (blue/ grey) 7.2MΩ
Outside wires (red/ yelow) 0.2MΩ
Blue/red combo - no reading
Yellow/ grey combo - no reading.

Pat - the neck did not glow initially - we replaced a resistor - then it started to glow. Still nothing on the screen - no dot or line.

My collegue has just cleaned around the internal resistance control of the yoke after he removed it before testing.

Model # of the tube is 240AKB4(N).

Attached is a pic of one zoomed shot.

I will try to get some more shots.

Thanks again

Jo

modem7 · Mar 2, 2009

So this is the unit that had the power surge!
Casualty list so far: BB3H diode, resistor, yoke.

Seen this company? : http://www.crtsolutions.com "Providing Innovative solutions for obsolete CRTs"
Maybe they do yokes as well.

Their CRT Safety document (http://www.crtsolutions.com/CRTSafety.pdf) suggests that RED/BLUE as horizontal and YELLOW/BROWN as vertical is a common usage.

Re the loose wire. Does the end look like a break or does it look like it's melted open?

MikeS · Mar 2, 2009

If it's a 'standard' monitor, maybe it'd be easier to replace the whole thing? Does it have a 10-pin edge connector by any chance?

m

Chuck(G) · Mar 2, 2009

I'd be willing to wager that the monitor is nothing more or less than some version of the Matsushita TR9DK1 OEM display used in Fanuc PLCs--you can still buy them today.

belairjo · Mar 2, 2009

Luck

Luck

Yup, the power surge looks like it's done a good job.

Without the schematics for the monitor it's been a challenge testing components.

We have voltage (2.2kV) up to the screen; with a glow in the tube. Symptoms the yoke is gone.

I'm searching www.crtsolutions.com now for a yoke. Thanks Modem 7 for the references - the magnet wire does look like it could have melted rather than break.

Mike: Yes the board is a 10 pin connector - we are now considering replacing the whole monitor - thanks for the suggestion model # etc.

My luck is running out on locating a yoke.

Cheers All

Jo

patscc · Mar 2, 2009

9 ~ 10 " monochrome monitor or old portable TV

9 ~ 10 " monochrome monitor or old portable TV

How's the junk situation over there ?
You might be able to scrounge the yoke from a 9 ~ 10 " monochrome monitor or old portable TV.
If you have access to a good amount of junk, you want to find a monitor/tv where the deflection angle is reasonable close (length of tube should be similar). If you post the total tube length, and the diameter of the CRT neck, maybe some people can start digging for a suitable yoke for you guys. I might have a couple of compatible yokes, I'll let you know after I get the measurements.
patscc
(The diagonal is around 9", right ?)

belairjo · Mar 2, 2009

Measurements

Measurements

I'm sure someone's got suitable 'junk' somewhere that we could use.

From the interest and help I've received so far I'm confident in finding it.

Here are the measurements:

Total tube length = 3 1/4 inches

Diameter of the CRT Neck = 0.8 inches.

Affirmative - the screen is 9" diagonal

Thanks for looking through your stuff for us, much appreciated.

belairjo · Mar 4, 2009

Stop Looking !!

Stop Looking !!

CRT Solutions Solves our Restoration Puzzle!

Thank You Modem7 for referring us to CRT Solutions

They were able to provide us with a circuit board and replacement yoke.

Thanks to all who offered assistance and advice - very much appreciated

:mrgreen:

Black & White TV Parts / Deflection Yolk

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