Ultra TR88 Pocket Transistor Radio - UK Vintage Radio Repair and Restoration Discussion Forum

Trannytuner · 23rd Sep 2019, 1:27 pm

Hello All
I am looking for some help with my newly acquired Ultra TR88 pocket radio.
The radio switches on and crackles when moving the volume control, but other than that nothing.
I was wondering if replacing the electrolytic capacitors would bring it back to life, I would love to get it working again, as a school friend had one of these back in the days of Radio Luxembourg.
I have the service sheet for it, but note the two larger electrolytics at the bottom of the set are 64uf 10v working, but the service sheet states these should be 40uf 10v.
Are the electrolytics tolerances very critical, as trying to get hold of some of these types is difficult.
For instance would a 40uf 50v working be ok?
Any help to get the wee set working again would be very much appreciated, as it is in good condition.
I'll try and upload some photos, many thanks.
Les

Andrew2 · 23rd Sep 2019, 1:49 pm

Hello Les.
You have the service sheet so you are off to a good start. Hold off from changing the electrolytics for now. The crackling volume control indicates that the audio stages, speaker etc are working, so the fault would seem to be in the RF/IF stages.
Use your meter to check the supply voltage on each end of R14 - obviously there should be something approaching 9v on one end, but what's on the other end? If it's around 7 or 8 volts, that's OK. Then move onto the voltages on the transistors and note any major discrepancy. Narrow the fault down to one stage, then one component.
Values of electrolytics in applications like this are not at all fussy. Back in the days of the Ultra, variations even when new could be 50% or more.
Good luck with it. I too have a soft spot for these small transistor radios, particularly the ones I had when I was at school in the 60's.

Trannytuner · 23rd Sep 2019, 2:03 pm

Hi Andy
Many thanks for the info, I'll certainly give that a go
Cheers
Les

FERNSEH · 23rd Sep 2019, 3:46 pm

Bought my Ultra TR88 in 1962 from a radio shop on Boundary Road Hove.
My example has the OC44M and OC45M transistors.

DFWB.

Trannytuner · 1st Oct 2019, 9:52 pm

My sincere thanks to everyone who replied to my post, the little Ultra is now in working order.
Moderator can you please close this post, thank you.
Les

Herald1360 · 1st Oct 2019, 11:33 pm

You could let us know what was actually needed to fix it!

Andrew2 · 2nd Oct 2019, 12:19 am

Yes, it would be nice to know, if only to help future owners of these sets.

crackle · 2nd Oct 2019, 6:38 am

Sometimes transistor radios of this age just start to work on their own after a few hours as the capacitors start to reform and voltages build to nearer their proper working voltages.
I wonder if that was the case here.
Mike

camtechman · 2nd Oct 2019, 11:42 am

Plessey made a very similar chassis for the Co-Op. Their model was the "Defiant A4".

Both the A4 & your Ultra TR88 have a switched tuner. MW tuning scale has 200 - 500 markings whilst there is a separate marking of 1500 for LW. The tuning gang has internal silver plated blades for switching from MW to LW. If not used regularly it will cause intermittent connection.

Trannytuner · 31st Oct 2019, 4:09 pm

Hello All
Re: The Ultra TR88 pocket radio.
I replaced c19 40uf and c17with a 47uf electrolytics, pulled from an old TV board, and the set worked fine, I probably should have gone with new components, but these sufficed. I watch too many Shango066 videos, it's starting to be an illness, how that guy repairs some of these things, I do not know, anyhow, many thanks for all your help.
Les

Trannytuner · 4th Nov 2019, 10:02 pm

Moderator can you please close the thread, many thanks.

AC/HL · 5th Nov 2019, 1:25 am

We don't close threads normally. They auto close in due course if there is no further activity. They can be reopened on request.

23rd Sep 2019, 1:27 pm	#1
Trannytuner Tetrode Join Date: Mar 2009 Location: Nr. Whitsome, Duns, Berwickshire UK. Posts: 56	Ultra TR88 Pocket Transistor Radio Hello All I am looking for some help with my newly acquired Ultra TR88 pocket radio. The radio switches on and crackles when moving the volume control, but other than that nothing. I was wondering if replacing the electrolytic capacitors would bring it back to life, I would love to get it working again, as a school friend had one of these back in the days of Radio Luxembourg. I have the service sheet for it, but note the two larger electrolytics at the bottom of the set are 64uf 10v working, but the service sheet states these should be 40uf 10v. Are the electrolytics tolerances very critical, as trying to get hold of some of these types is difficult. For instance would a 40uf 50v working be ok? Any help to get the wee set working again would be very much appreciated, as it is in good condition. I'll try and upload some photos, many thanks. Les Attached Thumbnails Last edited by AC/HL; 23rd Sep 2019 at 2:02 pm. Reason: B8

23rd Sep 2019, 1:49 pm	#2
Andrew2 Nonode Join Date: Mar 2010 Location: Dukinfield, Cheshire, UK. Posts: 2,036	Re: Ultra Tr-88 Pocket Transistor Radio Hello Les. You have the service sheet so you are off to a good start. Hold off from changing the electrolytics for now. The crackling volume control indicates that the audio stages, speaker etc are working, so the fault would seem to be in the RF/IF stages. Use your meter to check the supply voltage on each end of R14 - obviously there should be something approaching 9v on one end, but what's on the other end? If it's around 7 or 8 volts, that's OK. Then move onto the voltages on the transistors and note any major discrepancy. Narrow the fault down to one stage, then one component. Values of electrolytics in applications like this are not at all fussy. Back in the days of the Ultra, variations even when new could be 50% or more. Good luck with it. I too have a soft spot for these small transistor radios, particularly the ones I had when I was at school in the 60's. __________________ Andy G1HBE.

23rd Sep 2019, 2:03 pm	#3
Trannytuner Tetrode Join Date: Mar 2009 Location: Nr. Whitsome, Duns, Berwickshire UK. Posts: 56	Re: Ultra TR88 Pocket Transistor Radio Hi Andy Many thanks for the info, I'll certainly give that a go Cheers Les

23rd Sep 2019, 3:46 pm	#4
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Ultra TR88 Pocket Transistor Radio Bought my Ultra TR88 in 1962 from a radio shop on Boundary Road Hove. My example has the OC44M and OC45M transistors. DFWB.

1st Oct 2019, 9:52 pm	#5
Trannytuner Tetrode Join Date: Mar 2009 Location: Nr. Whitsome, Duns, Berwickshire UK. Posts: 56	Re: Ultra TR88 Pocket Transistor Radio My sincere thanks to everyone who replied to my post, the little Ultra is now in working order. Moderator can you please close this post, thank you. Les

1st Oct 2019, 11:33 pm	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Ultra TR88 Pocket Transistor Radio You could let us know what was actually needed to fix it! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

2nd Oct 2019, 12:19 am	#7
Andrew2 Nonode Join Date: Mar 2010 Location: Dukinfield, Cheshire, UK. Posts: 2,036	Re: Ultra TR88 Pocket Transistor Radio Yes, it would be nice to know, if only to help future owners of these sets. __________________ Andy G1HBE.

2nd Oct 2019, 6:38 am	#8
crackle Rest in Peace Join Date: Mar 2011 Location: Basildon, Essex, UK. Posts: 4,100	Re: Ultra TR88 Pocket Transistor Radio Sometimes transistor radios of this age just start to work on their own after a few hours as the capacitors start to reform and voltages build to nearer their proper working voltages. I wonder if that was the case here. Mike

2nd Oct 2019, 11:42 am	#9
camtechman Nonode Join Date: Jan 2008 Location: Milton Keynes, Bucks. UK. Posts: 2,552	Re: Ultra TR88 Pocket Transistor Radio Plessey made a very similar chassis for the Co-Op. Their model was the "Defiant A4". Both the A4 & your Ultra TR88 have a switched tuner. MW tuning scale has 200 - 500 markings whilst there is a separate marking of 1500 for LW. The tuning gang has internal silver plated blades for switching from MW to LW. If not used regularly it will cause intermittent connection. Attached Thumbnails __________________ When I die, please don't let my Wife sell my collection for the amount I told her I paid for it! Last edited by camtechman; 2nd Oct 2019 at 11:56 am.

31st Oct 2019, 4:09 pm	#10
Trannytuner Tetrode Join Date: Mar 2009 Location: Nr. Whitsome, Duns, Berwickshire UK. Posts: 56	Re: Ultra TR88 Pocket Transistor Radio Hello All Re: The Ultra TR88 pocket radio. I replaced c19 40uf and c17with a 47uf electrolytics, pulled from an old TV board, and the set worked fine, I probably should have gone with new components, but these sufficed. I watch too many Shango066 videos, it's starting to be an illness, how that guy repairs some of these things, I do not know, anyhow, many thanks for all your help. Les

4th Nov 2019, 10:02 pm	#11
Trannytuner Tetrode Join Date: Mar 2009 Location: Nr. Whitsome, Duns, Berwickshire UK. Posts: 56	Re: Ultra TR88 Pocket Transistor Radio Moderator can you please close the thread, many thanks.

5th Nov 2019, 1:25 am	#12
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Ultra TR88 Pocket Transistor Radio We don't close threads normally. They auto close in due course if there is no further activity. They can be reopened on request.