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Ferguson 3173

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PYE625
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The low contrast , no colour , washed out

Story of my life lol !!!

No, well done for achieving thus far :aad

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 01/08/2016 4:59 pm
The_Teleman
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Cheers Andrew , it's not been a labour of love this one
But in the words of Magnus Magnuson
I've started so I'll finish :aad

Chris

 
Posted : 01/08/2016 6:38 pm
The_Teleman
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Well the parts finally arrived mc1558 sound Ic
& the mc1327 for the lack of red drive
First to be fitted was the MC1558 this restored full sound
So then I turned to the MC1327PQ & low & behold this restored the red drive
But also improved the picture , as I said previously the picture looked washed out
Like a flat CRT but this was also resolved with replacing this I/C so the contrast now
worked normally
Still had no colour though

 
Posted : 05/08/2016 4:52 pm
The_Teleman
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The picture so far

 
Posted : 05/08/2016 4:58 pm
crustytv
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Time to disable the colour killer.

By the way you might find the 8500 decoder fault finding guide of use, it can be found here https://www.radios-tv.co.uk/thorn-8500-setup/

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Posted : 05/08/2016 5:12 pm
The_Teleman
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Thanks Chris

I have something similar but yours looks more comprehensive

 
Posted : 05/08/2016 5:24 pm
PYE625
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Getting better and better....convergence looking good :aad

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 05/08/2016 6:41 pm
The_Teleman
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Well I now know why this set was dead
It's without doubt due to a flashover , now , is it due to the damp conditions it's been stored in or the fact the smoothing capacitors have leaked or even a combination of the two.
The flashover took out the line output transistor , the MC 1327 , the MC1358 so why would it stop there .
Up to now I have found 2 s/c transistors vt111 & vt113 in the decoder & several out of spec capacitors .
On trying to set up the decoder as per the service information to hand everything was goin well until I went to adjust the ref osc coil L112 , the core was missing ?
Now why that would be missing I don't know
But I have heard in the past rental colour set having the ref osc stopped so they could be rented out as black & white sets .
Now it's pure speculation that this is the case here.
Having searched for a core to fit with the right thread & length I finally found one out of an old radio I/f stage, but no difference,
Thinking I'm going to have to dig my scope out of mothballs I went through the setting up procedure one more time without the scope & found vt110 to be faulty
Now I seem to remember somewhere that this device would fail for no apparent reason so being as there has been a flashover it's reasonable to assume it would have failed , and indeed it had , a replacement cured the fault with the ref osc.
One more time with the setting up & we have colour !
Wonderful ! Who needs a scope ?
So a full set up with convergence & geometry & we have a cracking picture in full living colour
Now I still insist this was NOT a labour of love but i did get a sense of achievement out of it.
Still think it needs an EHT tray as even with a replacement focus unit the focus is still at the top end of its travel .
All in all not a bad set considering it's a low end budget set . :aad

 
Posted : 05/08/2016 6:46 pm
PYE625
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Fantastic !
A cracking little set indeed. :aap

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 05/08/2016 6:58 pm
malcscott
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Well done!

 
Posted : 05/08/2016 7:22 pm
Tazman1966
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That's a very good result. I must dig my Ultra 6713 out for an airing.
By the way there's a 680k resistor on the CRT base panel in the beam limiter circuit. Check that it is not even slightly high or the grid bias will be low making the CRT look poor.

 
Posted : 05/08/2016 11:00 pm
The_Teleman
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Thanks guys

The new EHT tray arrived this morning
This was purchased hoping it would cure the focus fault
Well , it did the set now has a focused picture with the focus unit
in the centre of its travel rather tha at the top end . As far as I'm concerned now
This set is done
The only question now is do I keep it or trade it for a PYE set ?

Chris

 
Posted : 06/08/2016 11:42 am
The_Teleman
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This is the old EHT tray
As the date says 26 sept 1973
It's not done bad for a 43 year old EHT component

I would like to take this opportunity to say a big Thankyou
To Mikey 66 for the new focus unit
& Chris ( crusty tv ) for his invaluable service information

 
Posted : 06/08/2016 12:09 pm
crustytv
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This is the old EHT tray. As the date says 26 sept 1973, It's not done bad for a 43 year old EHT component

Hi Chris,

Can I ask what you intend to do with the old Tripler?

If you are keeping it no problem but If you intend to throw it out, could I ask that you check what potting has been used. Is it silicon or is it rock hard epoxy resin?

If its the latter ( epoxy) then its a bin job.

If it is the former and you still intend to dispose of it, I would offer to purchase it from you. Where possible I repair triplers so they can be used once again as can be seen from two examples below.

https://www.radios-tv.co.uk/brc-2000-tripler-rebuild/
https://www.radios-tv.co.uk/baird-700-series-tripler/

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Posted : 06/08/2016 12:44 pm
The_Teleman
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Hi Chris

You can have the old tripler
It's filled with a silicon type rubber I was just looking at it wondering if anything
Could be done with it
According to the circuit it's a EHT rectifier & a 150 meg resistor
I suppose the 150 meg has gone high after all this time .
I've also found an old tripler not sure but I think it maybe from a 3000/3500 series
You can have that too I won't be needing that .
Chris

 
Posted : 06/08/2016 1:56 pm
Jayceebee
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Wow what a result Chris, excellent work. :thumb

A note about the audio IC, the 8500 could possibly have three types fitted Texas SN76666N, Motorola MC1358P or RCA CA3065 all direct equivalents but the RCA type exhibited an annoying rumble/hiss at low volume levels.

Also for some reason the 4.43Mhz crystal used to lead a hard life, probably the most common cause of no colour.

John.

John.

 
Posted : 06/08/2016 2:25 pm
crustytv
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Hi Chris
You can have the old tripler It's filled with a silicon type rubber I was just looking at it wondering if anything Could be done with it.

Hi Chris,

That's great, thanks :aad I still have the HV potting compound from when I repaired the 2K tripler so it should be a simple case of digging out and replacing what has failed.

I've also found an old tripler not sure but I think it maybe from a 3000/3500 series. You can have that too I won't be needing that .
Chris

Thanks again that will come in handy too as with six 3k sets to maintain, spares are always good to have. Is the focus lead-out missing or is that just the photo angle? I will pop over sometime to collect that's convenient to you.

CrustyTV Television Shop: Take a virtual tour
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Posted : 06/08/2016 3:25 pm
yampy187
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Cracking little set!

Well done :thumb

 
Posted : 06/08/2016 10:12 pm
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