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Trade Chat AutoVox

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crustytv
(@crustytv)
Posts: 11997
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Topic starter
 

Today I was contacted by an ex Trade engineer called John, asking if I wanted approximately 15 Autovox PCBs before they went off to the tip. Well, of course, I said I would be delighted to take them to join my ever-growing 70s TV PCB stockroom, all of which goes to help maintain the TVs in my museum. But that's not what this post is really about, my curiosity was piqued. You see, Autovox is pretty much an odd-ball brand and quite rare.

What little I know about Autovox TVs can literally be written on a fag packet. They were Italian, were offered via Comet and were among the many continental imports in the 70s, plugging the gap due to British manufacturing not able to fulfil the demand. I know of only two sets that have survived, one I have, and the other owned by JonJo, or as he's known to many, 'Ojnoj'. Now there might be other survivors out there, but I'm fairly confident not in the 'known' community of collectors.

This is my 26" Autovox 2682

Autovox2682
Chas1
chas2

As luck would have it, a while ago I managed to obtain a large 8-page manual for the 2684. It contains the circuits, waveforms and PCB-layouts. For the most part it matches the 2682.

Autovoxcct

I asked John how he came by 15 Autovox PCBs, I had a sneaking suspicion what the answer would be, and I was right, yes he serviced them for Comet. Below you will find John's response to my query. I don't think John would mind me posting this on here, there is very little on the web about this brand of TV, and that is Radios-TV VRAT's remit, to capture and document the TV trade.

Hi Chris, well it is Indeed a long story. I am now "old " but back in the mid 1970's I spotted an advert in a Birmingham newspaper, it was placed by "Comet", Selly Oak branch. They were and had been for a while importing the AUTOVOX range directly from Italy. Within the range were car radios, two or more models of TV, 22 and 26 (25 ?) inch screens.

The advert related to the accumulating "heap" of service exchange panels, swapped out by the field engineering staff at many Comet branches around the UK. Essentially they had no-one with a suitable electronics engineering background to repair the panels, the design was partly lifted from the Mullard colour TV design lab and partly from a different source, but the overall electronic content was not what most TV engineers of the time were familiar with. 

I successfully applied for the job and was presented with two fully built test rigs, which were basically a 22 and 26 inch Autovox T.V. built around a skeleton frame of "dexion". All panels were thus very easy to access. I spent two years repairing hundreds if not thousands of the AUTOVOX TV boards on an exchange basis within the wider Comet service depts around the country. I was in a side warehouse at the Selly Oak Comet branch, where we also had many metres of racking carrying a full range of spare parts.  After two or three years the panel repairs were re-sited to a centralised Comet service branch in Leeds, at which time I left the activity. So if there isn't anyone left alive with hands-on experience from 1975 then it is just about myself !!! 

I do recall that the design was very solid and in comparison to much other electronic equipment, the number of "stock fauls " was pleasently small.  Regards John

There was a survey carried out in 1974 where it was stated the average UK TV had a 50/50 chance of breaking down in the next year. In 1974 2,600 TVs were sampled via a public questionnaire. Back then, very few sets we more than 4-years old, of that sample, about 60% were owned and 40% rented. Autovox appeared in that survey, the result can be seen below.

The first diagram covers reliability; the proportion of sets with zero breakdowns in the first 12-months.

The second diagram covers the average number of days out of action in the last 12-months

The third asked how likely would it be that you would buy or rent the same TV again

atest1
atest2
atest3

As you can see, Autovox faired pretty well on all the main surveys.

No brochures about but what I did find were a couple of B&W Autovox TVs from 1969, they were certainly funky designs, unlike the wooden TVs we imported. The final pic is an advert from 1975 for Autovox colour television, though not a UK advert.

autovox
autovoxlin1
avad

Finally

as a slight digression, most people collections feature the known UK brands, as does much of my collection. I'd like to fine tune the collection to one side covering the Thorn Stable 2000, through to TX100, the other side continentals and odd-balls. To that end I need to find such TVs as ASA, Finlux, Finlandia, Scantek. I'd also like to add the odd-balls, these would include, Telpro, Tyne, Spectra etc so a number of my non Thorn/continental sets will likely go over the next few years.

I hope that was of some interest, and I'll certainly update the thread with pics as and when all the boards arrive.


Admin Note:

As suggested, Comet Electrical posts split off to new topic

https://www.radios-tv.co.uk/community/television-broadcast-equipment/remebering-comet-electrical-stores/

 

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Posted : 23/05/2023 7:48 pm
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crustytv
(@crustytv)
Posts: 11997
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The rare Autovox CTV, now has spares thanks to the kind donation of ex trade engineer John. So very pleased to get these, and especially two LOPTs and one tripler. If you're reading this, John, as you can see, the package arrived safe and sound. The boards will all get a thorough clean, then filed away in the storeroom. When time permits, these will then be inspected and repairs effected where necessary.

I would just like to acknowledge what a thoroughly decent and kind individual John is. He did not want payment for the boards and shipped them at his own expense. He just wanted them to go to a good home. With humility, I say thank you, John, and do I believe they have ended up in the safe place you wished.

20230527 091245

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Posted : 27/05/2023 8:21 am
crustytv
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Over the next few days, I'll document the PCBs, along with the circuit, which as far as I can tell none of these exist anywhere else, certainly not the circuit.

20230527 210337

Starting with the Autovox decoder FG/01 and what appears to be a later release of the decoder, indexed as FG/0197 but over stamped with manufacturer's ink as 185.

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There are workshop markings on the delay lines on the FG/01 decoder, the delay line is a Sylvania with marker pen notation of WKS 5/3/92. From that, we can deduce the TV was perhaps still in use up until 1992.

The later decoder FG/185 has marker pen notation of " X JWC INT B-Y". From that, it's fair to deduce there is an intermittent B-Y

20230527 203932

Here is the print side of the PCB and the circuit

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Posted : 27/05/2023 8:00 pm
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slidertogrid
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If that set was still in use in 1992 it must have been well out of guarantee even an extended one. Did Comet service sets they sold on a out of guarantee chargeable basis? If so that surprises me as I thought the discount sheds were only interested in selling. 

 
Posted : 28/05/2023 8:52 am
crustytv
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Next up is the A/02 module, this combined PCB carries all RF, I.F. sound video. On the circuit diagram, this module is prefixed as A/0679, I guess a later release, as was the decoder I talked about above. The box I received also contained a nearly complete left side chassis assembly, which included the sound sub aluminium panel. You'll see that I have now assembled the chassis in the final photos.

20230528 093403
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The Circuit diagram and PCB plan view for RF, I.F. sound & video

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The Assembled left-side chassis

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In the final photo, you will note some interesting outputs, 5-pin DIN, speaker?, no idea what the rectangle was used for.

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Posted : 28/05/2023 8:54 am
irob2345
(@irob2345)
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We saw lots of strange TVs in Oz in the mad rush after colour launched here.

I've only ever seen one Autovox. That was in the mid '90s at the home of a friend of my sons. It was purchased in 1974, was still in use when I saw it. It had apparently been very reliable, but was looking a bit sad with a tired looking CRT and a convergence fault.

 
Posted : 28/05/2023 9:58 am
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crustytv
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The timebase & power supply chassis frame is not present, so I set about gathering the boards that would have made up that part of the TV. It appears I have everything but the power supply.

20230528 111608

Next I will document all the above and the convergence module.

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Posted : 28/05/2023 10:24 am
crustytv
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Next up Line timebase module I've two of these, again as with other modules, board prefixes suggest there appears to be a first gen (Z/01) and subsequent release (Z.0501).

The Z/01 module has distorted, with a banana like bow to the board, and has the tripler is missing. The Z.0501 (later release) is the best of the two, and is complete.

Z.0501

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Circuit and PCB plan view

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Z/01

20230528 132042
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Posted : 28/05/2023 12:26 pm
crustytv
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Field Timebase; module T.049 & Field Circuit

20230528 171953
20230528 172027
20230528 172312

Convergence I have two modules, H/01 GB and H/01. There are component differences between the two.

H/01 GB Convergence Module

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H/01 Convergence Module

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Posted : 28/05/2023 4:43 pm
Jayceebee
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Repaired a few of these and by far the most common fault I had was failure of the audio output transistor. Can't remember what the correct type was but an MJE340 from an 8000/8500 was a reliable replacement.

John.

 
Posted : 28/05/2023 7:27 pm
crustytv
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Posted by: @jayceebee

Repaired a few of these and by far the most common fault I had was failure of the audio output transistor

I never cease to be amazed at the varied TV sets that crossed your bench, John

Posted by: @jayceebee

audio output transistor. Can't remember what the correct type was but an MJE340 from an 8000/8500 was a reliable replacement

It was a BD159, indeed an MJE340, BF759, 2SC2899, 2SC3051, BD232 2N3739 & KT809A, are all viable substitutes

20230528 213053

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Posted : 28/05/2023 8:26 pm
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Jayceebee
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The bench that these crossed was the kitchen bench 😉 

John.

 
Posted : 28/05/2023 9:10 pm
crustytv
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Topic starter
 

To conclude the documentation of the Autovox Colour Television PCBs and circuits.

20230529 075535

This covers modules V/01, the CRT base panel (I have three of these). M/02, this board has all the A1 pots and switches. Finally, L/01 the mains inlet panel.

V/01 & Circuit

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20230529 075712

M/02 & Circuit

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L/01-02 & Circuit

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Hopefully, should anyone in the future be seeking technical information regarding the Autovox 2682/2684, will now come across this thread on a google search.

Edit:

Oh, almost forgot as there wasn't a power supply module in this batch of spares, the only one I have is in the set, and that's under 3 other TV's so not easy to get at to take a photo. For completeness, here is the cct for the PSU.

20230529 081629

p.s.

There are little daughter modules to catalogue, these will be done when I've cleaned the boards and carefully removed them to photo.

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Posted : 29/05/2023 7:10 am
Jayceebee
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Didn't know it was a full wave thyristor circuit as I never encountered any faults there. The circuit looks straight forward, no unobtainium components other than connectors it seems so if you need a PCB making to complete the chassis you know where to ask.

John.

 
Posted : 29/05/2023 11:20 am
crustytv
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I won't bore you all with endless photos of the Autovox boards being cleaned. However, by way of example, here is the field timebase after it was subjected to the cleaning process.

fldcleaned

I think that pretty much concludes this thread.

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Posted : 30/05/2023 7:42 pm
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Cathovisor
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Posted by: @crustytv

 

I think that pretty much concludes this thread.

...apart from "how/what did you clean them with?"

 

 
Posted : 30/05/2023 8:01 pm
crustytv
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Nothing special Mike, which is why I thought it not worth mentioning. You're right to point it out, someone new looking in might wonder how & what. 👍 Therefore, I used antistatic PCB foam cleaner, (readily available from RS) let the resulting fizz do its lift, agitate with a soft brush, rinse and thoroughly dry with a hairdryer. Particular attention to drying (blasting) any moisture from pots and coils.

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Posted : 31/05/2023 6:14 am
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sideband
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If there weren't too many inductors, I used to remove them and dump the rest in an ultrasonic bath. I could clean two or three boards at once that way. 

 
Posted : 31/05/2023 1:30 pm
Linescan87
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Hi Chris,

Great write up! Glad you got your hands on a few spare panels. As you quite rightly say they are very rare, only yours and mine are known of. I just looked it up and I have mine 4 years now, where does the time go? 

I need to get back to mine, the tripler failed in mine when I got it and I replaced it with one I had but its not right. Could you suggest a suitable alternative. Any chance of a few close up pictures of your tripler?

Thanks again,

John Joe, Ojnoj, jonjo, linescan87

 
Posted : 01/06/2023 9:32 pm
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crustytv
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Posted by: @linescan87

the tripler failed in mine when I got it and I replaced it with one I had but its not right. Could you suggest a suitable alternative. Any chance of a few close up pictures of your tripler?

Hi 'Oddge' 😉 

Although getting two line timebase panels in the recent haul, only one panel has a tripler. Naturally I would like to hang on to that in case the one in my TV goes south, had there been two I would have happily sent you one. However, if it were me and a universal tripler is not proving to be workable (can you explain why your substitute is not right?) I'd build one. 

It's not difficult, I've done it before both on a Thorn 2000 and a Baird M718 710-series chassis. Links below.

https://www.radios-tv.co.uk/vintage-electronics-blog-forum/brc-2000-tripler-rebuild/

https://www.radios-tv.co.uk/vintage-electronics-blog-forum/baird-700-series-tripler/

As we now have the circuit diagrams for the Autovox, it's pretty much a simple affair. You could use six BY182 EHT diodes and five .001uF 15kV caps. I reckon the BY182 diodes are likely to be too efficient, and the number might need reducing to 5 or even 4, it would need to be determined upon test. Of course, if you have a stock of CSD118XPA rectifier sticks (as used in the 2k/3k triplers, these are less efficient therefore ideal in that respect but make the tripler much larger. If it were me, I'd go with BY182.

tripcct

Here's my mock-up using BY182. Laid out in this way, the size is a tad larger than the Autovox one. However, once arranged in a small container, the footprint could be reduced right down to the correct size. Important thing is to use correct EHT potting compound, this easily obtainable.

trip

As requested, close up photos of the Tripler, though don't you still have the Autovox one you removed from yours for reference? I decided to give it a clean.

Before

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After

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CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
Crustys Youtube Channel: My stuff
Crusty's 70s Lounge: Take a peek

 
Posted : 02/06/2023 7:12 am
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