Another Ex BBC UHER 4000 Report Monitor - UK Vintage Radio Repair and Restoration Discussion Forum

Tombarnettuk · 6th Mar 2019, 11:35 pm

Hi I have just brought an Ex BBC (Scotland) Uher tape machine it has had the usual BBC mods as seen in the pictures. I also noticed on the board a track has been cut. Does anyone know why this might have been done. Also does anyone have any advice on how I might remove the yellow glue or paint on the pots that stops them being turned? Warm regards. Tom

Uncle Bulgaria · 7th Mar 2019, 12:19 pm

I can't say without seeing where it is on the diagram...and even then I'd be all at sea! I expect someone with far better electrical engineering knowledge than I will be along shortly, however.

As I just posted in t'other Uher thread, Elektrotanya has a PDF of 'BBC modifications' for the 4000 Report IC which could be worth perusing in case your board query is answered there, despite being a different model. https://elektrotanya.com/uher_4000_r.../download.html

Other manuals are here: https://elektrotanya.com/showresult?...oria=&kat2=all

I can't see your picture of the paint/glue in enough close-up detail to tell what it could be. Have you tried gently prising a bit off with a small screwdriver? If it's lacquered it will just flake away, and if it's still pliable sealant of some kind it might come away all at once. From my experience of my Report-L, attacking it with isopropyl alcohol wouldn't do any harm, though of course your mileage may vary...

barretter · 8th Mar 2019, 3:08 pm

If you find Elektrotanya a bit non-user friendly, you can also download the service manual at http://www.hifi-manuals.com/Uher/400...r-AV/downloads
You have to become a member but it's free. The pictures in the manual should enable you to pinpoint which part of the circuit the BBC have changed, but won't tell you why.

julie_m · 8th Mar 2019, 4:04 pm

The three-head Uher machines have a "neutral" position between each speed and the next, where the battery is disconnected; selecting a speed energises the motor, and the amplifier -- which can "wake up" more quickly than the motor -- is powered only when PLAY is depressed. The BBC mod locks the speed change knob on the "19" setting, and re-wires the motor so that it is switched on only when PLAY, WIND or REWIND is selected.

The other part of the BBC mod is to fix the recording level on manual. On an unmodified machine, "1" would be for speech and "2" for music.

There may well be variations in practice, since the modification was done locally by the BBC rather than at the Uher factory.

6th Mar 2019, 11:35 pm	#1
Tombarnettuk Retired Dormant Member Join Date: Mar 2019 Location: Poole, Dorsetshire, UK. Posts: 1	Another Ex BBC UHER 4000 Report Monitor Hi I have just brought an Ex BBC (Scotland) Uher tape machine it has had the usual BBC mods as seen in the pictures. I also noticed on the board a track has been cut. Does anyone know why this might have been done. Also does anyone have any advice on how I might remove the yellow glue or paint on the pots that stops them being turned? Warm regards. Tom Attached Thumbnails

7th Mar 2019, 12:19 pm	#2
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,339	Re: Another Ex BBC UHER 4000 Report Monitor I can't say without seeing where it is on the diagram...and even then I'd be all at sea! I expect someone with far better electrical engineering knowledge than I will be along shortly, however. As I just posted in t'other Uher thread, Elektrotanya has a PDF of 'BBC modifications' for the 4000 Report IC which could be worth perusing in case your board query is answered there, despite being a different model. https://elektrotanya.com/uher_4000_r.../download.html Other manuals are here: https://elektrotanya.com/showresult?...oria=&kat2=all I can't see your picture of the paint/glue in enough close-up detail to tell what it could be. Have you tried gently prising a bit off with a small screwdriver? If it's lacquered it will just flake away, and if it's still pliable sealant of some kind it might come away all at once. From my experience of my Report-L, attacking it with isopropyl alcohol wouldn't do any harm, though of course your mileage may vary...

8th Mar 2019, 3:08 pm	#3
barretter Heptode Join Date: Jan 2006 Location: Todmorden, West Yorkshire, UK. Posts: 870	Re: Another Ex BBC UHER 4000 Report Monitor If you find Elektrotanya a bit non-user friendly, you can also download the service manual at http://www.hifi-manuals.com/Uher/400...r-AV/downloads You have to become a member but it's free. The pictures in the manual should enable you to pinpoint which part of the circuit the BBC have changed, but won't tell you why.

8th Mar 2019, 4:04 pm	#4
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Another Ex BBC UHER 4000 Report Monitor The three-head Uher machines have a "neutral" position between each speed and the next, where the battery is disconnected; selecting a speed energises the motor, and the amplifier -- which can "wake up" more quickly than the motor -- is powered only when PLAY is depressed. The BBC mod locks the speed change knob on the "19" setting, and re-wires the motor so that it is switched on only when PLAY, WIND or REWIND is selected. The other part of the BBC mod is to fix the recording level on manual. On an unmodified machine, "1" would be for speech and "2" for music. There may well be variations in practice, since the modification was done locally by the BBC rather than at the Uher factory. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.