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Bush Tv148U broken tube

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Posts: 359

This is the set I got from a friend with the broken tube. I thought it was an early A640 chassis when I got it but according to the chassis sticker it is an A591. Very similar to the A640 but with separate tuners and a valve If panel.
I collected the set today from my lockup and had a look inside, it has a bit of woodworm in the base and more worrying there was fresh wood dust on the floor of the cabinet.
There are two date stamps inside the cabinet, it looks as if it was on the assembly line for a couple of days.... :aal
I have decided to strip the set outside and treat the cabinet before bringing it into the house.
The tube neck looks as if it was dealt a hefty blow, most of the phosphor has been blown off the screen and there is a small chip in the glass on the inside of the screen where presumably a bit of the gun impacted it!
For now I removed the chassis and broken tube, I intend to soak the cabinet in woodworm killer tomorrow. The woodworm is no where near as bad as the tube donor Top Rank set. the front on that set is crumbling!
Once I am happy with the cabinet I will fit the replacement tube, reform the smoothers and decide what to do about a lopt.
What is that bl@@dy wood worm like about these Rank sets!? :bbd
I do have a Mother in law with a large chest (careful!) freezer... :aaq If I treat it with woodworm killer and then freeze the cabinet for a week or so is that a fairly guaranteed cure?

Topic starter Posted : 29/06/2015 12:21 am
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Posts: 5477

Given that we are due a heatwave this week, putting it in a car in full sun with all the windows shut will also do the trick - but the freezer is more certain. I'd do it the other way round though: freeze it for a couple of weeks then treat it. More domestically acceptable, apart from anything else!

Posted : 29/06/2015 12:39 am
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Posts: 836

This is the set I got from a friend with the broken tube. I thought it was an early A640 chassis when I got it but according to the chassis sticker it is an A591.

For days I've been wondering what the chassis before the A640 was called and now you've finally put me out of my misery.

The A591 was of course also used in a lot of interesting Murphy sets.

Posted : 29/06/2015 3:36 am
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Posts: 601

Such as the V159U that I have :bba . although mine doesn't work that well on 625 as the picture is very washed out and definitely not watchable even in a dark room :bbd .


Posted : 29/06/2015 2:31 pm
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Posts: 359

Yes I had always (incorrectly) thought that the A640 chassis covered all of the series and that there were just three versions of the If panel. The early ones having valves, the middle model having germanium transistors and the last being silicon.
I have a few sets with this series of chassis I will check the numbers, but it looks as if the chassis number was different depending on the If panel. A640 being the last dual standard guise with silicon transistors.
Anyway I have taken Mike's advice and wrapped the cabinet in a big plastic bag and dumped it in the freezer for a while.
It can have a freezing fortnight while we have a sweltering one!
I stuck my head in the loft today, I was going to see if I could find my spare lopt ... :aaq it was much too hot up there, so I will resume the search later when it has cooled down a bit !

Topic starter Posted : 29/06/2015 6:37 pm
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Posts: 10839

For those that wish to follow along with this repair, I've loaded the three ( Service and cct/Tuner/Alignment) Trader service sheets 1812,14 &15 into the library. I have combined them into one file called Bush TV148U Trader, R&TS data was already present but I know most prefer Trader.

Posted : 01/07/2015 9:45 am
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Posts: 359

Thanks Chris. Most useful! :thumb
I have got the set all back together now. I gave the cabinet a good douse of woodworm killer. I poured a little inside and then rotated the cabinet around so as the inside including the front got a good soak.
It's time in the freezer caused on or two joins to loosen but nothing major that a bit of wood glue couldn't sort. I then filled the holes and refitted everything back into the cabinet.
A good polish and it really has come up well. The set works quite well considering it has had almost nothing done to it. there are a few minor issues to sort.
It is still running on the borrowed lopt at the moment. I have been experimenting with the duff one. First I tried replacing the overwind with one I had from a Plessey transformer. It worked for a while but still ballooned badly. once switched to 625 the EHT fell off and the DY heater went out.
I then removed the overwind and fitted a 1500 3 stick tripler with a 180pf from top cap of the PY to chassis. This gave me a dim big picture but it is stable, doesn't balloon and works on 625. I guess I need a 5 stick tripler...
Apart from that the sync is a bit weak, if the contrast is advanced it cogs and bends, and the sound goes distorted after a while.
So still plenty to do!

Topic starter Posted : 12/07/2015 5:26 pm