Radio City MultiTester Model 446. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

peter.sables · 17th Feb 2014, 9:46 pm

Hi Cris.

That's OK. You can have it. As you say nice to look at if nothing ells. You win some, most of the time. hi.

pete

Can you close this thread..

Herald1360 · 17th Feb 2014, 11:49 pm

Thanks very much- I'm waiting with anticipation

peter.sables · 18th Feb 2014, 4:13 pm

Hi Chris

Thank you. I got the classic transistors in the post today. I've got a job for one or two. Hope you have fun with the meter.

regards. Pete G4MRU

AC/HL · 18th Feb 2014, 11:31 pm

One post deleted, please use the PM system for personal correspondence.

Herald1360 · 19th Feb 2014, 6:25 pm

And I've received the meter

I think this thread is dead, now......

If I sort out any more issues with it and get it to read correctly, I'll do a Success Story on it

Chaparal · 20th Feb 2014, 7:16 pm

FYI,
here is an original schema for the
Radio City MultiTester Model 447 VOM

maybe similary to the 446 model.

Peter.

Herald1360 · 20th Feb 2014, 7:57 pm

Hi Peter.

Thanks for the posting. The 447 looks very much like what I finally arrived at for the 446, except that the Rx100 range switch position has moved and the universal shunt uses standard resistor values rather than the (closeish) set that I calculated. Also it uses only a single diode rather than the half bridge arrangement of the 446.

While I'm at it, I've had a further look at my 446- as Pete said at some point the meter sensitivity is down-~1.2mA, probably lost magnetism. There are also some open elements in the shunt. Paradoxically the combination of these two faults means that the voltage ranges are about right

The worst problem, though,is the state of the input sockets which are quite badly corroded in some cases. They're neither wander size nor 4mm, given its US origin I think they may be 1/16" or 3/32". In any case, to do anything with them would be more difficult than a mass replacement.

17th Feb 2014, 9:46 pm	#21
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Radio City MultiTester Model 446. Hi Cris. That's OK. You can have it. As you say nice to look at if nothing ells. You win some, most of the time. hi. pete Can you close this thread..

17th Feb 2014, 11:49 pm	#22
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Radio City MultiTester Model 446. Thanks very much- I'm waiting with anticipation __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

18th Feb 2014, 4:13 pm	#23
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Radio City MultiTester Model 446. Hi Chris Thank you. I got the classic transistors in the post today. I've got a job for one or two. Hope you have fun with the meter. regards. Pete G4MRU

18th Feb 2014, 11:31 pm	#24
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Radio City MultiTester Model 446. One post deleted, please use the PM system for personal correspondence.

19th Feb 2014, 6:25 pm	#25
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Radio City MultiTester Model 446. And I've received the meter I think this thread is dead, now...... If I sort out any more issues with it and get it to read correctly, I'll do a Success Story on it __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

20th Feb 2014, 7:16 pm	#26
Chaparal Hexode Join Date: Apr 2007 Location: Wiesbaden, Germany Posts: 333	Radio City MultiTester Model 446, 447 FYI, here is an original schema for the Radio City MultiTester Model 447 VOM maybe similary to the 446 model. Peter. Attached Thumbnails

20th Feb 2014, 7:57 pm	#27
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Radio City MultiTester Model 446, 447 Hi Peter. Thanks for the posting. The 447 looks very much like what I finally arrived at for the 446, except that the Rx100 range switch position has moved and the universal shunt uses standard resistor values rather than the (closeish) set that I calculated. Also it uses only a single diode rather than the half bridge arrangement of the 446. While I'm at it, I've had a further look at my 446- as Pete said at some point the meter sensitivity is down-~1.2mA, probably lost magnetism. There are also some open elements in the shunt. Paradoxically the combination of these two faults means that the voltage ranges are about right The worst problem, though,is the state of the input sockets which are quite badly corroded in some cases. They're neither wander size nor 4mm, given its US origin I think they may be 1/16" or 3/32". In any case, to do anything with them would be more difficult than a mass replacement. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O