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Old 23rd May 2007, 10:33 pm   #39
Tazman1966
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Join Date: May 2006
Location: St Albans, Herts, UK.
Posts: 2,193
Default Re: Pye CT205 - a partial success story!

Hello Folks.

Well my work on the Pye is complete

The final bits and bobs that I did are described here.

First the annoying blue line convergence. What was happening were that the blue horizontals were bowed and could not be adjusted with RV29 the Blue Amplitude pot. You could get a sort of compromise effort by adjusting RV28 the Blue tilt and L51 Blue Parabola but then after a few minutes it would gradually drift out again and there seemed to be a bit too much heat around the wirewound in series with RV28 (which seemed to be very scratchy). Out came the meter and I found that RV29 was stuck at 20R so as I hadn't got a replacement, I took the pot apart and cleaned and bent the wiper up to make a better contact. I put it back together and tried again...still no adjustment. Then I did what I should have done in the first place and checked the little 10R wirewound in series with it and found that it was open circuit. The overheating around RV28 should've given me that clue as the two systems are in parallel with each other. I replaced it with a 7W one - the only one to hand and a bit on the large size but I just managed to make it fit! Now the control worked and with the aid of my trusty crosshatch DVD did the convergence from start to finish and I'm very pleased with the result. I must say that even at 7W the new resistor gets quite hot too.

Next was the push button unit. I suspected that the springy contacts on buttons 1 and 2 may have been snapped at one end although I seem to remember that unless they snapped off completely the whole unit jammed up. Sure enough the contacts had snapped of completely and were nowhere to be seen so no repair to that However with the buttons out it gave me the chance to give them a really good scrub and boy did they need it. All of the grooves were caked in brown gunge. You can see the clean result in the picture.

As for the dry joint causing the intermittent rainbows...who knows? I could not get it to do it anymore

Time to do a real good clean on the cabinet. The soapy water was filthy and yellowy brown afterwards but the top and sides are in remarkably good condition. Maybe the nicoteen preserved them.Next what to do about the chipped and missing bits of veneer on the front surround. Well I said I had an easy fix for that. I stripped the remaining pieces off and then sanded down the chipboard until smooth and then using some matt black insulation tape stuck it to the smooth clean edges and then trimmed the excess with a Stanley knife. I hope you agree it complements the black control panel etc.

Finally a polish up, a set up (inc reducing the EHT for added reliability) and a soak test in the garage it was time to transfer the set to the house and give it pride of place on the sideboard like the Philips and the Dynatron before it.

Here are some pictures. I'll have to split them between two posts. Hope you like them and soon the Pye and Dynatron will be side by side in my little collection alcove in the back bedroom but more on that another time!

All the best,
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All the very best,
Tas
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