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Old 7th Feb 2020, 11:31 pm   #1
Semir_DE
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Default Repairing my Bush TV62

Hello Everyone,

Last year I was able to buy a Bush TV62 on Ebay. One of my very nice colleagues from our London office had picked it up for me and it had been sitting in our company warehouse for a while. Since I did not trust the regular forwarders to deliver this fragile TV to Germany in one piece I decided to make a trip to the UK by car taking the whole family along in August last year. Apart from the challenge of driving on the left and the traffic congestion on the M25 It turned out to be a very nice visit to the greater London area (we had stayed in Ruislip) during which I had a chance to visit the British Vintage Wireless and Television Museum (BVWTM) (thanks Jeffrey B. for arranging that) and many other places. The family also enjoyed the visit to the UK very much especially my daughter who had never been to the UK before.

Now I have begun to work on this nice little TV and have started by giving it a thorough cleaning. Here is an image of the CRT before cleaning. I believe this TV had been kept in a smokers household or pub judging from the sticky dirt on all parts:

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Here are a few images of the signal and main chassis after I had removed them from the cabinet:

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I have also measured the CRT and it seems to have good emission. I use my µTracer to measure CRTs using the diode formed by the cathode and g1 as an anode. This gives a good indication of the emission. In this case the CRT can deliver more than 10mA when the g1 "anode" is at 100V with respect to the cathode. Since the µTracer uses very short pulses for measurement this relatively high current will not harm the CRT - no worries.

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Also the filament seems OK as it draws exactly 300mA when fed from a 6.3V source. So hopefully it does not have any partial shorts as others have reported in this forum regarding this model.

After some cleaning the CRT looked a lot better:

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It seems the main Electrolytic capacitors in the power section are still OK as they measure about 200µF and have an ESR of around 1Ω. I an wondering if will have to replace all the capacitors in the TV as they seem to be sealed with a kind of wachs. I will make some measurements and test their values and isolation before making any decision on that.

Next I will present the cleaned chassis and LOPT and any progress on the repair. Any hints from users who have successfully repaired this TV model would be very welcome. I do have the 9 page service information which should make the repair much easier. One surprise for me was the PCL83 valve that is being used in the audio and vertical deflection sections. This was a new valve that I had not encountered in any other TV I have repaired so far.

Cheers

Semir
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Old 8th Feb 2020, 12:08 am   #2
linescan87
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Default Re: Repairing my Bush TV62

Hi Semir,

I have just finished one off these for the Hurdy Gurdy radio museum here in Ireland. At first my CRT had a partial heater short but it seems to have cleared itself and has been reliable for the last few weeks.

You will have to change all the wax caps as they will be electrically quite leaky, I also had to replace the low value electrolytics on the timebase deck.

These sets work really well when done.

Best of luck, John Joe.
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Old 8th Feb 2020, 12:29 am   #3
ronbryan
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Default Re: Repairing my Bush TV62

Semir

I found that a simple wooden frame fixed to the timebase/power chassis with screws and quick clamps was the best way to work on the chassis when it was out of the cabinet. It saves the transformers and mains dropper from being damaged if you have a lot of work to do and allows the chassis to be turned to alternative positions if needed.

The chassis illustrated had perished rubber wiring looms to be replaced as well as having the later version single tag-board with hard-to-access wax capacitors mounted on both sides.

Ron
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Old 8th Feb 2020, 10:21 am   #4
mark pirate
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Default Re: Repairing my Bush TV62

Quote:
These sets work really well when done.
There are several Bush sets that use these chassis, the RF deck is particularly easy to work on with those nice handles fitted

As John Joe has said, all wax caps should be changed on sight.
The main electrolitics usually hold up well, the LOPT is also very reliable.
I think you will be impressed by the picture quality, these sets are capable of excellent results once restored.

Our family TV (T67, same chassis) lasted over 17 years with no repairs, a testament to how reliable these sets were for their time.


Mark
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Old 23rd May 2021, 6:26 pm   #5
Semir_DE
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Default Bush TV62 Repair follow up

Dear all,

after a long time of working on other projects I recently had the time to complete this one. To be honest I had dreaded the work of re-wiring all the controls and CRT base as the original cables were all falling apart. But I finally got a the motivation to do it, while being on furlough I had to keep busy with something after all

I have come up with an efficient system of replacing the wires which works as follows:

- disconnect one end of old wire
- solder that end to a long "helper wire"
- pull the other end of the old wire until the end with the helper wire shows up
- de-solder old wire and use it to cut a new wire with exact same length
- attach to helper wire and pull it back through same path in reverse
- once done solder the new wire to the original components

By working in that way the new wires will be in exactly the same positions as the old ones and I get the correct lengths. Also by doing one at a time there is not much room for error.

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Old wires I had replaced.

I also added a new mains cable as I did not have the original one which fits on the two prongs. So I added a regular euro-cable. Not original I know but safe.

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New power cord.

After that I replaced all the wax covered capacitors except the flat ones which seemed to measure ok. They were all leaky and had 50% higher values, as some of you had predicted.

I have not so far had to replace any of the electrolytic capacitors. They all seemed to have values close enough to what was printed on them.

I also opened the tuner and cleaned the band I/ band III switches.

Now the moment of truth had come so I put everything back in place, re-installed the magnets on the CRT in roughly their original positions and slowly powered up the set. After some time the valves lit up and I was greeted with a faint raster and everything seemed to operate normally, no smells, no smoke, no crackling. Power consumption was around 125W.

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First sign of life...

After some adjustments of the magnets and other controls I had a pretty good bright raster. Now was the time to feed a signal to this nice set. I fired up my Hedghog and set it to ch.10 in test card mode. After selecting that channel lo and behold an image appeared, but it was upside down. I had plugged in the vertical deflection coil the wrong way round. That bit was easily corrected and after a few more adjustments I was rewarded with a very nice image indeed.

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After some adjustments.

Audio, however was still missing and by accident I had touched one of the EF80s in the audio IF section. With a crackle the audio appeared. Time to play some Sinatra videos...

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Real image

I will add some finishing touches like:

- cleaning all the valves pins and base contacts
- fixing the height control which is "crackling"
- find the cause of intermittent vertical raster collapse

I'll post the final result when I'm done, but I have to say that I am impressed how well this little TV works after more than 65 years (I'm "only" 58, so it is older than me) outside of the capacitors everything else including the LOPT was still in good working order - Wow!
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Old 24th May 2021, 12:22 am   #6
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Default Re: Bush TV62 Repair folow up

nice picture!
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Old 24th May 2021, 9:48 am   #7
mark pirate
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Default Re: Bush TV62 Repair folow up

Several Bush models used this chassis, my parents had a T57 17" console set, it ran for 17 years without any service calls!

Bush sets were well built & very reliable, they are certainly my favourite make.
I recently restored a TV32 from 1953 (first set to use the 14" Bakelite cabinet)
It was literally a barn find in a very poor state, but now restored, the picture quality is quite amazing for a 68 year old set, certainly comparable with much newer sets.

Rotten rubber wiring can be a pain to replace, I usually number each wire at both ends then chop out the loom and replicate it with PVC wire, the replace it.


Mark
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Old 24th May 2021, 1:22 pm   #8
Semir_DE
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Default Re: Repairing my Bush TV62

Hello everyone,

I would like to thank the admins for merging my two threads!

Yesterday I had the set on soak test and I noticed that the height would slowly decrease. The culprit turned out to be C14 which was leaky - I guess I should've replaced it from the get go. While at it I also exchanged C22. Now the image is near perfect:

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I have now integrated this lovely TV into my " multi-system TV corner". Here I can show 405, 525/60, 625 and 819 with the same content originating from a PC playing a 720p or 1080p file. This allows me to demonstrate the different formats side by side:

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I use the following configuration:

As a player I use VLC in "clone" mode which allows me to output three identical video windows at the same time. The PC I use has an Nvidia graphics card that can deliver three different signals at the same time:

- #1 is VGA 819 to my VGA2RF converter: 819 line signal
- #2 is HDMI 1024x768 to an HDMI to composite converter box: 625 line Pal signal
- #3 is DVI to the PC monitor.

#1 is modulated to channel F3 by my VGA2RF box
#2 is modulated on channel E5 and/or E7 by means of a cable head station modulator
#2 is fed to a Hedghog converter to get 405 this is set for channel B2
#2 is also fed to my PAL/NTSC standards converter to get NTSC (EIA) 525/60

The NTSC signal can be modulated to channel E7 alternatively

Besides the PC I have several other sources such as a sat box, DVD player, Laser Disc Player, U-Matic machine, VHS deck and a small media player. for selection I have a 12x2 Matrix. For test signals I use a Grundig VG1001 modulated to channel E11.

This post concludes this project. I am very happy to have this nice little TV added to my collection.

Cheers

Semir
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Old 24th May 2021, 10:19 pm   #9
patrickgnl
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Default Re: Repairing my Bush TV62

I wish i had the knowledge and capability to do what you have done. One thing we both have in common is I too have a Sony 9 90UB and a 9 90UM…

I would certainly love too see how the respective standards compare. Well done and thanks for posting, a very interesting read….

Patrick
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Old 25th May 2021, 10:15 am   #10
slidertogrid
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Default Re: Repairing my Bush TV62

What an excellent job you have done !
I too would be interested to compare the picture quality of 405 625 and 819 lines.
The heavy blanket type dust seems to be a product of coal fires, if a set was used near the fire the convection effect would draw in the dust and the chassis acted as a filter. I have seen chassis' covered in soot, add a smoker or two to the room and it becomes brown and sticky...
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Old 25th May 2021, 4:11 pm   #11
Semir_DE
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Default Re: Repairing my Bush TV62

Hi Patrick, Hi Slidertogrid,

Thank you for the kind words!

Many of the things I have presented here are the result of countless hours of trial and error and I had to learn many things over time.

If there is an interest in the forum I could open an extra thread detailing all the necessary steps on how to output e.g. 625 and 405 simultaneously with identical content from a PC running Linux.

I find a PC to be very useful for such tasks. In another project I use one to output 4 AM "stations" on different frequencies at the same time. For that I use a USB VGA adapter as a D/A converter.

From what I've heard the AM broadcasts in the UK will be closed down in the near future, so such a project might be of interest as well.
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