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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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7th Jul 2021, 12:15 am | #1 |
Heptode
Join Date: May 2010
Location: Warminster, Wiltshire, UK.
Posts: 682
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Ekco T542 (Pye 169 chassis)
I didn’t really want this set as I got to many other sets, but if it wasn’t for me it would of gone to landfill. I couldn’t let that happen so being the only bidder I won it. It’s got the original legs and in excellent condition apart from a chip on the front .
I believe it’s basically a Pye with different war paint . All ready I’m stuck.. I snipped the main filter cap and slowly powered up on a Variac. Nearing full voltage hey presto nothing happened except R32 started smoking. It's not dust it’s overload. I tried the set 3 times and quickly had to switch off. I can’t see anything why it would do this. Components near by look and test OK apart from a cooked C34 near a wire wound resistor. That’s now been replaced. VT5 transistor has in the past been replaced. I’m stuck so hopefully someone can help Andy
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I bet that car doesn't have a suppressor. Last edited by bionicmerlin; 7th Jul 2021 at 12:26 am. |
7th Jul 2021, 12:36 am | #2 |
Heptode
Join Date: May 2010
Location: Warminster, Wiltshire, UK.
Posts: 682
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Re: Ekco T542 (Pye 169 chassis)
Just a couple more pics . Hopefully jog a few memories.
Showing R32. Andy
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I bet that car doesn't have a suppressor. |
7th Jul 2021, 6:52 am | #3 |
Heptode
Join Date: Apr 2003
Location: Cornwall, UK.
Posts: 986
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Re: Ekco T542 (Pye 169 chassis)
First , I would remove VT5. Is it S/C?
Then power up and check your HT lines, and the voltage at the junction of R32 & R33. Good luck. Cheers. SimonT.
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The honesty of imperfection.......... |
7th Jul 2021, 8:04 am | #4 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,428
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Re: Ekco T542 (Pye 169 chassis)
VT5 was a stock fault but usually O/C base emitter but no reason it cannot be S/C.
When you say nothing happened did that include no heaters lit up?
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Frank |
7th Jul 2021, 9:25 am | #5 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Ekco T542 (Pye 169 chassis)
BF178 is a bit close to its limits here.
I would have used a BF259 or BF337 as replacement back then. |
9th Jul 2021, 2:25 am | #6 |
Heptode
Join Date: May 2010
Location: Warminster, Wiltshire, UK.
Posts: 682
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Re: Ekco T542 (Pye 169 chassis)
Bit of a update..
And thanks so far. I removed the said transistor. Testing it on a meter I would say it’s ok. Not shorted. But it appears to be a BF257. Not One that you recommended. By removing the transistor R32 its not smoking. Having said that it’s still running very hot. Due to the smoking I probably didn’t give the set a chance to warm up . The valves lite up and I am now getting sound.. I have measured the HT results showing in the picture. According to the reading they are much to high. Andy
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I bet that car doesn't have a suppressor. |
9th Jul 2021, 9:45 am | #7 |
Nonode
Join Date: Jan 2004
Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area.
Posts: 2,965
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Re: Ekco T542 (Pye 169 chassis)
I liked the 169 chassis it gave very good pictures. What are the Voltages like around VT5? It could be being turned hard on either due to a problem around the contrast control RV3, C31 being leaky or if you are unlucky to high a voltage on pin12 of the IC.
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Simon BVWS member |
9th Jul 2021, 2:17 pm | #8 |
Heptode
Join Date: May 2010
Location: Warminster, Wiltshire, UK.
Posts: 682
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Re: Ekco T542 (Pye 169 chassis)
The voltage without the transistor at R32/33 is 156 volts. . I have had a little look and test around the contrast . It seems in order . I will have a better look later and maybe put the transistor back in and test again and voltages . Thanks everyone Andy
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I bet that car doesn't have a suppressor. |
9th Jul 2021, 2:53 pm | #9 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Ekco T542 (Pye 169 chassis)
257 just a lower gain version of 259. If the transistor runs a bit hot, try one of the
push on corrugated metal heatsinks for TO-5/TO-39 transistors - you may have one. As the can is collector voltage, ensure it can't touch any other component. |
10th Jul 2021, 2:02 am | #10 |
Heptode
Join Date: May 2010
Location: Warminster, Wiltshire, UK.
Posts: 682
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Re: Ekco T542 (Pye 169 chassis)
Well THE GOOD ,BAD and probably THE UGLY
The good bit . I put the transistor back in with a heat sink as suggested. I did check C31 it appears ok , the contrast pot is abit suspect so turned it to its lowest setting and switched on Chassis hinged down looking out for smoke . This time no smoke and also I got a picture and sound. Great. After a few mins no smoke , even better. Now the BAD bit . Stupid me, with the chassis still down and the set still working I push the chassis back towards the upright position . There is a pop and I loose sound and picture. Now the Ugly bit. I don’t know what I done wrong to cause the pop , I can’t see any reason or any loose wiring. Or maybe just coincidence it would of gone anyway. I guess the fault is in the IF stage as I get a blank screen and a hiss from the volume so the amps working. It’s getting late so I will have look later. Andy
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I bet that car doesn't have a suppressor. |