Bendix BC221 Frequency Meter - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

beamcurrent · 15th Oct 2010, 9:27 pm

Here is the PSU circuit

Regards, Brian

Herald1360 · 15th Oct 2010, 10:44 pm

That's just about a textbook illustration of a stabilised power supply. Nice!

Richard ZS6TF · 17th Oct 2010, 5:43 am

I have 2 of these units. One is destined to be a VFO in a valve AM transmitter project where it can be used without modification.

RobinBirch · 19th Oct 2010, 9:57 pm

Guys,
A copy of the manual and a photo/copy of the circuit would be brilliant. I've got a couple of 221s and at least one of them is worth keeping original so I would like to make a good copy of the PSU to pop in the bottom.

Regards

Robin

RobinBirch · 19th Oct 2010, 9:58 pm

Just seen the photo of the circuit. Brilliant.

Robin

Dave UXB · 6th Nov 2010, 7:42 pm

Quote:

Originally Posted by RobinBirch

Andy,
You wouldn't have the circuit for that PSU would you?

Regards

Robin

From what I could see of the picture, it's a simple "series hard-valve stabiliser" [I sweated blood over this circuit when I was on my Fitters' course].
Pure magic and almost infinitely stable.

Good Luck.

beamcurrent · 6th Nov 2010, 10:33 pm

Having posted the circuit I thought you might like to see what the PSU looks like.

The small box in the first picture is the power input connector, switch and fuse box. This PSU arrangement is more common in the wood case version of the BC221.

Brian

QQVO6/40 · 7th Nov 2010, 12:29 pm

Thank you to all who have put info on this subject as I have a couple of BC221s. One I purchased at an amateur radio field day last Feb. It is a large one with the green box and the canvas cover. It is immaculate. And it is fitted with the power supply which has just been shown above. A most hearty thank you to you Brian and all of the other people in this wonderful forum. Only thing wrong with this one - a leaky grid coupler to the audio amp. Easy fix and spot on for accuracy too. tnx again.

15th Oct 2010, 9:27 pm	#21
beamcurrent Heptode Join Date: Mar 2008 Location: Camberley, Surrey, UK. Posts: 805	Re: Bendix BC221 Frequency Meter Here is the PSU circuit Regards, Brian Attached Thumbnails

15th Oct 2010, 10:44 pm	#22
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Bendix BC221 Frequency Meter That's just about a textbook illustration of a stabilised power supply. Nice! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

17th Oct 2010, 5:43 am	#23
Richard ZS6TF Diode Join Date: Apr 2008 Location: Johannesburg, South Africa. Posts: 4	Re: Bendix BC221 Frequency Meter I have 2 of these units. One is destined to be a VFO in a valve AM transmitter project where it can be used without modification.

19th Oct 2010, 9:57 pm	#24
RobinBirch Hexode Join Date: Apr 2003 Location: Cotswolds, UK. Posts: 465	Re: Bendix BC221 Frequency Meter Guys, A copy of the manual and a photo/copy of the circuit would be brilliant. I've got a couple of 221s and at least one of them is worth keeping original so I would like to make a good copy of the PSU to pop in the bottom. Regards Robin

19th Oct 2010, 9:58 pm	#25
RobinBirch Hexode Join Date: Apr 2003 Location: Cotswolds, UK. Posts: 465	Re: Bendix BC221 Frequency Meter Just seen the photo of the circuit. Brilliant. Robin

6th Nov 2010, 10:33 pm	#27
beamcurrent Heptode Join Date: Mar 2008 Location: Camberley, Surrey, UK. Posts: 805	Re: Bendix BC221 Frequency Meter Having posted the circuit I thought you might like to see what the PSU looks like. The small box in the first picture is the power input connector, switch and fuse box. This PSU arrangement is more common in the wood case version of the BC221. Brian Attached Thumbnails

7th Nov 2010, 12:29 pm	#28
QQVO6/40 Hexode Join Date: May 2009 Location: Newcastle, Australia Posts: 319	Re: Bendix BC221 Frequency Meter Thank you to all who have put info on this subject as I have a couple of BC221s. One I purchased at an amateur radio field day last Feb. It is a large one with the green box and the canvas cover. It is immaculate. And it is fitted with the power supply which has just been shown above. A most hearty thank you to you Brian and all of the other people in this wonderful forum. Only thing wrong with this one - a leaky grid coupler to the audio amp. Easy fix and spot on for accuracy too. tnx again.