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Old 30th Sep 2019, 3:16 am   #1
RestorationRod
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Default EKCO TP-308 restoration

A couple of weeks ago I managed to get an EKCO TP-308 off e-bay for an outlay of £5.00

It was dirty but complete. The plastic top cover and screen bezel were removed and cleaned up a treat. Needless to say a full restoration was required. All of the electrolytic and wax capacitors were replaced. This necessitated the removal of the tube. Fortunately the service instructions tell you how to do this as its required to do an alignment.

Next I traced the wiring from the mains input and found the on/off + volume switch had fallen apart. This was duly replaced and a resistance reading across the heater chain obtained. (including the tube)

A comment at this point. Hold the safety advice guys - I have 50+ years of experience of working on live chassis TV and used to test cables up to 264 kV

So with the HT rectifier mains feed disconnected and using an isolation transformer, switched series incandescent bulb and a variac slowly brought up the voltage. Hoo - flipping - ray!! The valves lit up (series heaters so all or nothing).
Turn off and say Phew!

Next connect in HT rectifier, isolate output and check HT - yup 200v DC + (open circuit)

Turn off - discharge caps and connect HT to rest of set. Attach EHT meter to tube connector, AVO on DC current in series with HT and voltmeter across it.

Turn up variac and .... 12 kV on the tube connector, 195v DC at 200 mA HT and a nice healthy set of heaters. Turn off and say Phew! (again)

Next up tube back in and check for a raster.
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Old 30th Sep 2019, 8:01 am   #2
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Default Re: EKCO TP-308 restoration

Please could you post some photos, I don’t have a circuit for the TP308 but its probably similar to other Ekco TV’s from that era.
I don’t remember fixing any but we would not have sold many and there is much I have forgotten from 60 years ago.
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Old 30th Sep 2019, 8:16 am   #3
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Default Re: EKCO TP-308 restoration

Great little portable and as Frank has mentioned, very similar to most Ekco chassis of the 50's. The FM radio also gives a good account of itself.

As with all Ekco models there are a few common faults such as decoupling capacitors and capacitors that look like resistors. Rather than go through the repeats it might be worth searching for EKCO T330/331 on this site's archive. Most of the faults mentioned are listed and apply to the TP308. The CME1402 Mazda picture tube is usually OK. It is a 90 degree type. John. [PS I think this needs to be in the TV section].

Last edited by AC/HL; 30th Sep 2019 at 4:23 pm. Reason: Thanks John, moved.
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Old 30th Sep 2019, 9:11 am   #4
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Default Re: EKCO TP-308 restoration

I have the full set of circuits and service notes. All components have been checked for the correct value ( I have good H-P in circuit L-C-R tester) and replaced if out of spec. Pots are paxolin or similar and look flimsy. Knobs are integral to the pots and held on with a spire fastener. Very nasty!!. Any old pots that get changed (the vol/on-off already has) will have their knobs cut off and be drilled for 6mm (1/4") shafts and put on the new ones.
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Old 1st Oct 2019, 8:15 am   #5
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Default Re: EKCO TP-308 restoration

Post photos - How?
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Old 1st Oct 2019, 8:17 am   #6
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Default Re: EKCO TP-308 restoration

Does this attach?
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Old 1st Oct 2019, 8:57 am   #7
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Default Re: EKCO TP-308 restoration

Attached perfectly.

Good luck! It seems you have a very good start there...
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Old 5th Oct 2019, 4:08 pm   #8
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Default Re: EKCO TP-308 restoration

This pots with the spire clips were used a lot by Ekco, they did fail like other pots but no more than others.
I found if they required changing it had to the complete control, trying to fit the old spire clip and knob to a new track and wiper was not really successful.
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Old 16th Oct 2019, 5:23 pm   #9
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Default Re: EKCO TP-308 restoration

Hello Rod,How are you getting on with the TP308? John.
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Old 24th Oct 2019, 2:27 pm   #10
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Default Re: EKCO TP-308 restoration

Picture uploaded
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Old 24th Oct 2019, 2:37 pm   #11
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Default Re: EKCO TP-308 restoration

Better picture
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Old 24th Oct 2019, 7:24 pm   #12
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Default Re: EKCO TP-308 restoration

Hello, congratulations on a successful restoration, your TP308 is producing a fine picture. May I ask a favour please, could you post some pictures of inside the set. I would really appreciate an underside view of the RF chassis showing how the cam on the end of the tuner spindle operates the TV-FM slide-switch.

Itís a long story but almost 50 years ago I successfully converted a TP308 to receive UHF 625 lines following an excellent article by K Cummins in the January 1969 and February 1969 issues of Practical Television. Despite all the warnings and caveats the conversion was reasonably straightforward and worked well.

The line timebase seemed quite happy running at the higher frequency and gave a stable lock without the need to add flywheel sync. The only slight issue that I remember was the line flyback time being too long, resulting in a shadow as the first few microseconds of each line started before the spot had returned to the edge of the screen. At the time I experimented with blanking circuits and achieved an acceptable result but never completely cured it.

The original VHF tuner was removed and its space filled with a UHF tuner, and a transistorised IF module (from a Pye 40F I think) plus various tag strips, prototype boards, small mains transformers, etc. all strung together to make everything work. During conversion, the lever that operates the TV-FM switch was removed and subsequently lost. Attached are a few pictures of inside my converted TP308, none of the changes was documented for future reference and I stare in awe and wonderment at what was achieved at such a young age.

After conversion, I used the set it in my bedroom for several years until something more modern was acquired. During that time, the only faults that developed were in the UHF tuner and in desperation at some stage I replaced the push-button tuner with an older rotary tuned valve unit.

I still have the set and one day plan to restore it back to its original state (but not this side of Christmas). The only missing component that I will need to fabricate is the lever that links the cam on the tuner spindle to the TV-FM slide-switch. Hence my request for a picture.

Thanks

Len
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Old 24th Oct 2019, 7:32 pm   #13
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Default Re: EKCO TP-308 restoration

Great picture! What did you have to do to get it that good? Just needs the line lin adjusted. [I think that is a turnbuckle on the lopt cover] and the scan coils straightened. John.
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Old 24th Oct 2019, 8:25 pm   #14
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Default Re: EKCO TP-308 restoration

Hi
I replaced all the electrolytic and wax capacitors plus the line and frame oscillator valves.
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Old 25th Oct 2019, 11:07 am   #15
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Default Re: EKCO TP-308 restoration

Pictures attached
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Old 25th Oct 2019, 11:11 am   #16
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Default Re: EKCO TP-308 restoration

The over scan is due to the 82R resistors having gone high (92R) replacements ordered
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Old 25th Oct 2019, 10:58 pm   #17
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Default Re: EKCO TP-308 restoration

Thank you for the internal pictures, they will be a great help as I restore my TP308 back to its original VHF 405 line condition. Thanks also to the other contributors who have highlighted some of the common faults to look out for. Hope to report progress in the new year.

Len
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Old 27th Oct 2019, 10:45 am   #18
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Default Re: EKCO TP-308 restoration

Quote:
Originally Posted by RestorationRod View Post
Hi
I replaced all the electrolytic and wax capacitors plus the line and frame oscillator valves.
Hello Rod, Don't forget the caps that look like resistors they are usually O/C. There is one on your first picture on the right just below the screening can [post15].There is also a .1uf waxie in the tuner that decouples the AGC line. It can give strange effects when it leaks. J.
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