Ekco LOPT Preservation? - UK Vintage Radio Repair and Restoration Discussion Forum

Kat Manton · 29th Sep 2006, 10:55 pm

Hi,

Something I've been thinking about, is there anything I should do with the LOPT in the Dynatron TV30CK I'm resurrecting?

The perspex support structure is in good condition and isn't burnt or disintegrating, the windings don't look like they've been in any distress and check ok for continuity. (The Mazda U25 EHT rectifier had 'The White Mark of Death' and a NOS Mullard replacement has been sourced.) The windings are a bit 'furry', I've carefully brushed the dust off but some has stuck on the wax around the edge of the EHT overwind and elsewhere and won't just brush off.

Should I attempt to clean it up a bit better and if so, has anyone got any suggestions? I've not got a dishwasher, by the way

I'm wondering if I should coat the windings in some sort of lacquer and maybe coat the perspex housing as well.

As it seems to be in pretty good nick at the moment, but I know they can fail in various ways, I'd be interested in any suggestions which might ensure it lasts another 50 years

Regards, Kat

Mike Phelan · 30th Sep 2006, 9:03 am

Kat
I think that the main reasons for demise were the field service gorillas' poor soldering of the U25, coupled with a layer of sticky dust on the top part around the valve.
If the acrylic shell is clean I think that is all you need.

FERNSEH · 30th Sep 2006, 12:54 pm

Hi Kat,
I'm certain that your line output transformer is OK. The best course of action is just leave it in it's present condition.

Here's a picture of the transformer casing I made for an Ekco TMB272.

DFWB.

Heatercathodeshort · 30th Sep 2006, 7:46 pm

Hello Kat,
I would strongly suggest that you leave the LOPT as it is. The Ekco windings were of the best and I have never known the windings to fail.

The problem is the plastic case that broke down with age.
It usually started when the sets were around 5 years old. The case began to break down across the connections to the U25 starting with slight corona and then severe tracking that had little or no effect on the picture!

This resulted in many fires as the smouldering continued when the set was turned off. A sweet sickly smell leaked from the set when the transformer began to break down giving a clue....

My very first job when still at school was to make paxolin replacements for the whole Ekco range. I still have some notes!

Don't worry about your set. The LOPT is fine and will give years of experimental fun. Don't spray it with anything.

Regards John.

Kat Manton · 3rd Oct 2006, 12:37 am

Hi,

Thanks for the advice; I've already removed the transformer from the chassis and carefully cleaned the housing inside and out. I'll leave it at that.

So, trouble starts when there's a few years' worth of dust build-up and EHT starts tracking across the dust. Therefore it seems the best plan is to periodically check it and keep it clean as a preventative measure.

Given the remarkable condition the transformer is in the set can't have had much use. Oddly the 'VHF' bulb glass is seriously darkened, so maybe this set was used more as a radio... It's also possible that EHT rectifier failure (there's a very small crack in the seal where the outer envelope meets the cathode support structure) meant the set was either taken out of service or used as a radio...

It's just possible that the aparrent lack of use means the Mazda CRM172 might have some life left in it as well... time will tell...

Regards, Kat

29th Sep 2006, 10:55 pm	#1
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Ekco LOPT Preservation? Hi, Something I've been thinking about, is there anything I should do with the LOPT in the Dynatron TV30CK I'm resurrecting? The perspex support structure is in good condition and isn't burnt or disintegrating, the windings don't look like they've been in any distress and check ok for continuity. (The Mazda U25 EHT rectifier had 'The White Mark of Death' and a NOS Mullard replacement has been sourced.) The windings are a bit 'furry', I've carefully brushed the dust off but some has stuck on the wax around the edge of the EHT overwind and elsewhere and won't just brush off. Should I attempt to clean it up a bit better and if so, has anyone got any suggestions? I've not got a dishwasher, by the way I'm wondering if I should coat the windings in some sort of lacquer and maybe coat the perspex housing as well. As it seems to be in pretty good nick at the moment, but I know they can fail in various ways, I'd be interested in any suggestions which might ensure it lasts another 50 years Regards, Kat

30th Sep 2006, 9:03 am	#2
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: LOPT Preservation? Kat I think that the main reasons for demise were the field service gorillas' poor soldering of the U25, coupled with a layer of sticky dust on the top part around the valve. If the acrylic shell is clean I think that is all you need. __________________ Mike.

30th Sep 2006, 12:54 pm	#3
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: LOPT Preservation? Hi Kat, I'm certain that your line output transformer is OK. The best course of action is just leave it in it's present condition. Here's a picture of the transformer casing I made for an Ekco TMB272. DFWB. Attached Thumbnails Last edited by FERNSEH; 30th Sep 2006 at 1:07 pm. Reason: Add picture

30th Sep 2006, 7:46 pm	#4
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: LOPT Preservation? Hello Kat, I would strongly suggest that you leave the LOPT as it is. The Ekco windings were of the best and I have never known the windings to fail. The problem is the plastic case that broke down with age. It usually started when the sets were around 5 years old. The case began to break down across the connections to the U25 starting with slight corona and then severe tracking that had little or no effect on the picture! This resulted in many fires as the smouldering continued when the set was turned off. A sweet sickly smell leaked from the set when the transformer began to break down giving a clue.... My very first job when still at school was to make paxolin replacements for the whole Ekco range. I still have some notes! Don't worry about your set. The LOPT is fine and will give years of experimental fun. Don't spray it with anything. Regards John.

3rd Oct 2006, 12:37 am	#5
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Re: LOPT Preservation? Hi, Thanks for the advice; I've already removed the transformer from the chassis and carefully cleaned the housing inside and out. I'll leave it at that. So, trouble starts when there's a few years' worth of dust build-up and EHT starts tracking across the dust. Therefore it seems the best plan is to periodically check it and keep it clean as a preventative measure. Given the remarkable condition the transformer is in the set can't have had much use. Oddly the 'VHF' bulb glass is seriously darkened, so maybe this set was used more as a radio... It's also possible that EHT rectifier failure (there's a very small crack in the seal where the outer envelope meets the cathode support structure) meant the set was either taken out of service or used as a radio... It's just possible that the aparrent lack of use means the Mazda CRM172 might have some life left in it as well... time will tell... Regards, Kat