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 A Tale of Two H.M.V.'s Part one of several
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 Return to top of page · Post #: 1 · Written at 12:40:02 PM on 6 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

Hi Folks.

Last weekend I began the restoration of a couple of H.M.V. Colour televisions.

The first one I'll describe has a C211 chassis. It is single ended console, walnut in colour, with gold trim and knobs. Very attractive looking. These things really were built to be not only a television, but also a lovely piece of furniture. This set, works to a point. It can produce a picture, but has numerous issues.

A little bit of history of this set. This is the last set of this model ever produced.
It was made up from parts that were left over when production finished. An entire set was made from the left over parts, that would have been used by the service, and spares parts departments.
It differs from all the rest by having neither the chassis type, ink stamped onto the chassis, nor a serial number stamped into the, metal swing-up, come crashing-down, chassis.
Next, it does not have the Colour TV History card on the rear of the cabinet.

The two sets will be used as test beds for each other. The first repair that I have to make is to repair the Power Supply module of the second set. It had gone BANG in a spectacular fashion, and led to the demise of that set. One wonders, for how many years has it been dormant?

When the pictures of the set appear, note the four different types of printed circuit board used on this chassis. There should be only one or two. We have representatives from the entire series run.


Wayne.

HMV Television
HMV Television
HMV Television


 
 Return to top of page · Post #: 2 · Written at 11:40:22 AM on 7 April 2019.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 176

Best of luck with the C211's. They generally were a box of faults unless all of there many ill's were sorted out.
The power supply suffered from heat faults caused by mounting wire wound PW5 and PW10 resistors mounted next to small value electrolytics.
The mod was to mount these resistors on tag strips attached to the side of the power supply frame.
The pins on the Hor O/P board were prone to cooking and burning holes in the board.
The convergence board wire wound pots would frequently fail etc, etc.
And to top it off the chassis when hinged up tended to fall out of it's hinges and neck the CRT.
I have a full service manual for C211 and C212 if you need any info
I cut my teeth on them as an apprentice. A baptism of fire!!
Many of them were dead on arrival and had to be repaired before delivery.
They really spelled the end for local manufacture of CTV's for EMI. A real pity as the following model C221 sets were very nice.
To late to save them though.


 
 Return to top of page · Post #: 3 · Written at 6:39:50 PM on 7 April 2019.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 5331

Photos uploaded.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 4 · Written at 7:00:27 PM on 7 April 2019.
Pitchersj's avatar
 Location: Albury, NSW
 Member since 2 July 2017
 Member #: 2134
 Postcount: 113

I will be watching this restoration with a great deal of interest.
I want a HMV colour set, but I want a an early one that is reliable 😄

Aesthetically these sets are just beautiful and very classy.
It's a shame their performance and reliability was so poor.

Just goes to show that beauty is only skin deep.


 
 Return to top of page · Post #: 5 · Written at 9:51:17 AM on 9 April 2019.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 176

Their performance in fact was very good and when sorted made a very nice picture. Just not for long in many cases.


 
 Return to top of page · Post #: 6 · Written at 11:36:52 AM on 11 April 2019.
Daro's avatar
 Location: Tanawha, QLD
 Member since 22 December 2012
 Member #: 1263
 Postcount: 38

The chroma and video boards look like the ones used in the C221, C231 (Philips 20AX CRT) chassis.


 
 Return to top of page · Post #: 7 · Written at 8:05:34 AM on 12 April 2019.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 176

I'd like to find a C221 or C231 as a project.
They still had the nice timber cabinet but were a quantum leap better in reliability.
They were, in my opinion, as good as the Kriesler by then.
They were a pleasure to align and kept their alignment with no drift in convergence to worry about.
If only they had brought that model out first, they would have had a winner on their hands.


 
 Return to top of page · Post #: 8 · Written at 8:53:23 AM on 20 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

 A Tale of Two H.M.V.'s Part two of several.

Hi Folks, now that it is Easter and I have ten days off, I've managed to begin the repairs of the two H.M.V.'s.

First were the two power supply modules. I began with the non-working module.
The electrolytic capacitors were all replaced and some of the A.E.E. Capacitors, but not the tantalum cap which tested alright. I have no idea where the rest of C126 went. Only the base of the cap remained. The wrong transistor type had been fitted for the error amp. The main filter cap, which tested O.K. Was changed simply because I did not have the time to reform it properly. Its replacement is quite a deal smaller and had a different pin spacing, necessitating a hole to be drilled through the board to take the new cap's pin spacing.

I started the power supply in position, and used a variac to avoid any spectacular, blinding flashes.
The power supply started reliably from a an input of 160volts.
The 25 volt rail varied less that one volt over an input of of 160volts to 250v.

Nothing became hot, so the board was cleaned and a sticker with the overhaul date attached to the heatsink.

Power supply No.2
This was the working power supply. I did not expect to find any thing major, maybe just some poor solder joints and some so-so electrolytic caps. Quite frankly, after testing the caps, I'm surprised that it worked at all. Anyway, seven electros later, and all is well with the world.

Please note. The power supply module used in the C211 chassis is not compatible with the power supply used in the C221 chassis.

HMV Circuit


 
 Return to top of page · Post #: 9 · Written at 11:18:35 AM on 20 April 2019.
Irext's avatar
 Location: Werribee South, VIC
 Member since 30 September 2016
 Member #: 1981
 Postcount: 176

Do either of the Power Supplies have the large wire wound resistors on tagstrips mounted to the side of the frame?
This was a mod to stop them cooking the electrolytics on the pcb.


 
 Return to top of page · Post #: 10 · Written at 12:13:00 PM on 20 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

Irext,

I e-mailed you some pictures.

I have many more as I am documenting the whole repair process.

Wayne.


 
 Return to top of page · Post #: 11 · Written at 4:33:20 PM on 20 April 2019.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 5331

Photo uploaded to Post 8.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 12 · Written at 7:32:19 AM on 24 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

Hi Daro.

Sorry about taking so long to reply.

The Luminance board, PCB6, and the chrominance board, PCB7, are interchangeable between the C211, C212 chassis and the
C221, C231 (transistor output) chassis.

Furthermore, the I.F. board PCB5, later called PCB5R (R for rotary Tuner) can be swapped between the two chassis types.
From memory, the sets with the varicap tuners had a removable sub-board attached to the I.F. board to provide the A.F.T. function for the sets fitted with push button tuning.

After the introduction of the C221 and C231 chassis model, PCB5 meant I.F. board with A.F.T. board, PCB12 mounted on top.

I hope this is of benefit to you.

Wayne.


 
 Return to top of page · Post #: 13 · Written at 10:09:42 AM on 24 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

A Tale of Two H.M.V.'s Part 3.

Now that I had the power supply for the H.M.V. Ambassador rebuilt and fitted, I needed to do some testing before switching on.

I found the scan thyrsistor shorted. Now they do not just go short for no reason. I found burnt pins on the scan board connector. Links had been run from the board and soldered to the connector pins. I decided to use the known good scan board for now. I switched on with the tripler disconnected. Up came sound, and a screwdriver held near the connector to the tripler drew an arc, although not as long as I had expected.

No smoke, flames, nor loud noises.
All good so far. Next I connected the tripler. The large blue triplers fitted in this chassis are far more reliable than the smaller green Philips triplers. Anyway, E.H.T. appeared, but no raster. Next I discovered that the three G2 controls had been wound all the way down, and that the 2.2M ohm G2 coarse adjustment control, had suffered abuse from some, “turkey with a screw driver.”

I would have thought that I would have no trouble finding a replacement 2.2M ohm pot.
Not so. Around 200 pots of all types, and only one 2.2M ohm pot. The said pot was made to fit and again I switched on. Still no raster. The one thousand volt rail was a little low and also the E.H.T.
I did not want to wind up the “set e.h.t.” control as the scan board was adjusted for the other set.
For now, I wound up the screen controls and screen preset control and at last got a raster.

The raster that I got was not all that impressive, but this just the start. For now, I will replace the damaged picture tube socket, fortunately, I have forty-five, new, old stock sockets. At least that should go smoothly.

Until I next get some time to work on the sets, bye for now.

Wayne.


 
 Return to top of page · Post #: 14 · Written at 9:41:48 AM on 27 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

A Tale of Two H.M.V.'s Part 4 of Several.

This time I replaced the last of the electros on the scan board and overhauled the vertical driver board. Just a note. Buying caps at Jaycar is becoming ever more difficult. Common caps seem never to be in stock, and don't forget a loan application if you wish to buy anything high voltage, or large capacitance. Anyway, I had to use higher capacitance caps where not critical. I guess that the engineers would love to have used what I put in, but because of size and cost constraints did not.
Inrush surge currents/time constants proved to be of no problem.

Next to my horror, the fine tuning mechanism broke whilst tuning in a test pattern from a modulator. The slipping clutch had become too tight, and over the years the grease turned to glue, and off snapped the plastic post holding the intermediate gear. Too much to describe the repairs to the gear assembly and clutch, but while I had the tuner out, I cleaned its contacts. They had been giving me trouble.

With the set back together again, I decided to finally get around to setting up the convergence and geometry. That completed, the set looked better, but the picture was still very poor. This should prove interesting as both sets have identical faults. It is time to call in the heavy artillery, (C.R.O.)

Out of time for now, I have to renew my membership of the H.R.S.A. Or as my wife calls it.
“The Hysterical Radio Society of Australia”. Perhaps we are all a little crazy. Still, it does keep me out of the pubs.

Bye for now.

Wayne.


 
 Return to top of page · Post #: 15 · Written at 4:12:03 PM on 28 April 2019.
Labrat's avatar
 Location: Penrith, NSW
 Member since 7 April 2012
 Member #: 1128
 Postcount: 264

A Tale of Two H.M.V.'s Part 5 of Several.

Hello again.

Here are some photos of the restoration so far.

1. The result of the tube test. This was done before I invested any time into the chassis. As it was a good result,I want ahead.

HMV Tuner


2. The tuner removed for repairs. The broken fine-tuning mechanism was a real pain to repair and took hours to get working properly. After a couple of days, I realised that after testing several lubricants for the clutch, I think that I will try “Tap Repair Grease” from Bunnings, on the other tuner, If I can find the intermediate gear.

HMV Tuner


3.Note the gauge of wire and number of turns on the biscuits of the tuner. The comparison between the lower and upper ends of the tuning are easy to see.

HMV Tuner

HMV Tuner


4. A few of the tools used in the repairs so far. I have not had to use a hammer just yet. We will see how it goes.

HMV Tuner


 
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