UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Closed Thread
 
Thread Tools
Old 15th Feb 2020, 4:39 pm   #1
Malcolm G6ANZ
Octode
 
Malcolm G6ANZ's Avatar
 
Join Date: Feb 2006
Location: Bristol, UK.
Posts: 1,030
Default Marconi CR300 PSU

I have been given a tatty CR300 with power supply. It was stored in a garage for many years so is need of a rebuild!
I thought I'd start with the PSU. The receiver came with whet appears to be the original manual however the PSU section is totally different to the actual object.
The manual, all other information on the net shows the PSU as having one fuse and one switch on the front and another switch inside. Mine has two fuses and no internal switch. Also the tappings/links for the various supply voltages are labelled differently. The manual indicates them as numbered links and mine has them as voltage links coupled with letters.
So does anyone have a correct circuit?
I probably wont use the receiver on DC of any voltage as the vibrator is missing, but I will change the caps so in the future DC operation might be possible.

Malcolm
Attached Thumbnails
Click image for larger version

Name:	IMG_2029.JPG
Views:	274
Size:	122.0 KB
ID:	199031   Click image for larger version

Name:	IMG_2030.JPG
Views:	279
Size:	140.1 KB
ID:	199032   Click image for larger version

Name:	IMG_2031.JPG
Views:	253
Size:	132.2 KB
ID:	199033  
Malcolm G6ANZ is offline  
Old 16th Feb 2020, 8:23 am   #2
Ed_Dinning
Dekatron
 
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,171
Default Re: Marconi CR300 PSU

Hi Malcolm, there were full details of the CR series in a comprehensive RB article a few years ago

Ed`
Ed_Dinning is offline  
Old 16th Feb 2020, 9:47 am   #3
G3VKM_Roger
Heptode
 
G3VKM_Roger's Avatar
 
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 772
Default Re: Marconi CR300 PSU

This may be the cct you have already but if not:-

http://www.vmarsmanuals.co.uk/archiv...300_Manual.pdf

73

Roger/G3VKM
G3VKM_Roger is offline  
Old 16th Feb 2020, 11:28 am   #4
Malcolm G6ANZ
Octode
 
Malcolm G6ANZ's Avatar
 
Join Date: Feb 2006
Location: Bristol, UK.
Posts: 1,030
Default Re: Marconi CR300 PSU

Roger, yes that is the circuit I already have. For my PSU it is incorrect. Thanks anyway.
From what I can find on the net all the PSU's are for the single fuse and numbered tappings.
Ed, I presume RB is Radio Bygones? If so their search engine doesn't come up with any results for Marconi or CR300.
If you can let me have the issue date I'd be willing to buy the download to get the information.

Malcolm
Malcolm G6ANZ is offline  
Old 16th Feb 2020, 12:51 pm   #5
G3VKM_Roger
Heptode
 
G3VKM_Roger's Avatar
 
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 772
Default Re: Marconi CR300 PSU

OK Malcolm,

I have a hard copy of that Radio Bygones and it does have several pages on the Marconi CR-series. It's Issue no 31 , dated Oct/Nov 1994. P/M me for more info. The article says the manual for the CR300 is T1864/2 but seems to be the same as the VMARS link.

73

Roger/G3VKM

Last edited by G3VKM_Roger; 16th Feb 2020 at 1:11 pm. Reason: Add
G3VKM_Roger is offline  
Old 16th Feb 2020, 1:20 pm   #6
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Marconi CR300 PSU

Never seen that type before, mine was the single fuse on the front panel.

Lawrence.
Attached Thumbnails
Click image for larger version

Name:	CR300-1 001.jpg
Views:	198
Size:	65.3 KB
ID:	199070  
ms660 is offline  
Old 16th Feb 2020, 3:40 pm   #7
AndyWright
Tetrode
 
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 91
Default Re: Marconi CR300 PSU

This style of PSU was also used with the Marconi Mercury receiver. You may want to download the manual and have a look at the psu schematics. Let me know if you cant find it on the web.

Andy G4OJY
AndyWright is offline  
Old 16th Feb 2020, 3:46 pm   #8
AndyWright
Tetrode
 
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 91
Default Re: Marconi CR300 PSU

I've just had a look at my Marconi Mercury manual, and the schematic for the type 889A PSU clearly shows 2 fuses on the AC input to the transformer.

Andy
AndyWright is offline  
Old 16th Feb 2020, 5:45 pm   #9
Malcolm G6ANZ
Octode
 
Malcolm G6ANZ's Avatar
 
Join Date: Feb 2006
Location: Bristol, UK.
Posts: 1,030
Default Re: Marconi CR300 PSU

Eureka! Thanks Andy that's the PSU I need.The mains and low voltage input look the same as mine and the layout diagrams are the same.
Many thanks.

Malcolm
Malcolm G6ANZ is offline  
Old 27th Oct 2022, 12:53 pm   #10
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,192
Default Re: Marconi CR300 PSU

Thread reopened at Julesomega's request.
__________________
Graham. Forum Moderator

Reach for your meter before you reach for your soldering iron.
Station X is offline  
Old 27th Oct 2022, 1:11 pm   #11
Julesomega
Nonode
 
Julesomega's Avatar
 
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
Default Re: Marconi CR300 PSU

I have just got hold of a Type 889 PSU which I intend to use for an Electra rx but I cannot find a circuit diagram for this. The Mercury & Electra require a Type 889A, and the schematic is included in the receiver manual which is widely available.

The differences must be minor, but an original diagram is always helpful, especially when dealing with something that has been 'got at' as in this case - can anyone help?
Attached Thumbnails
Click image for larger version

Name:	PSU Type 889_small.jpg
Views:	92
Size:	127.8 KB
ID:	266939  
__________________
- Julian

It's good here
Julesomega is offline  
Old 27th Oct 2022, 1:26 pm   #12
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Marconi CR300 PSU

Quote:
Originally Posted by Julesomega View Post
I have just got hold of a Type 889 PSU which I intend to use for an Electra rx but I cannot find a circuit diagram for this. The Mercury & Electra require a Type 889A, and the schematic is included in the receiver manual which is widely available.

The differences must be minor, but an original diagram is always helpful, especially when dealing with something that has been 'got at' as in this case - can anyone help?
I have the schematic etc for the 889 PSU, I'll post a link soon as poss.

Lawrence.
ms660 is offline  
Old 27th Oct 2022, 1:31 pm   #13
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Marconi CR300 PSU

I found it sooner than I thought (Manual page 36 and onward for the 889 PSU details)

Lawrence.
Attached Files
File Type: pdf marconicr300.pdf (2.31 MB, 59 views)
ms660 is offline  
Old 27th Oct 2022, 1:58 pm   #14
Julesomega
Nonode
 
Julesomega's Avatar
 
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
Default Re: Marconi CR300 PSU

Thanks so much Lawrence, that's perfect!
__________________
- Julian

It's good here
Julesomega is offline  
Old 27th Oct 2022, 4:54 pm   #15
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Marconi CR300 PSU

Quote:
Originally Posted by Julesomega View Post
Thanks so much Lawrence, that's perfect!
Out of interest what's the rectifier valve in yours?

Lawrence.
ms660 is offline  
Old 28th Oct 2022, 11:59 am   #16
Julesomega
Nonode
 
Julesomega's Avatar
 
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
Default Re: Marconi CR300 PSU

Whatever it was has been replaced by three silicon diodes, don't ask why three, one is in series with the junction of the others - maybe it was a convenient anchoring point for the two cathodes

This one has the usual mains voltage selection switch with the rather cute arrangement of a rotary switch operated by a lever arm which is accessible with the cover off
Attached Thumbnails
Click image for larger version

Name:	Type 889 PSU [r].jpg
Views:	56
Size:	111.8 KB
ID:	267011   Click image for larger version

Name:	Type 889 PSU detail.jpg
Views:	52
Size:	90.0 KB
ID:	267012  
__________________
- Julian

It's good here
Julesomega is offline  
Old 28th Oct 2022, 12:33 pm   #17
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
Default Re: Marconi CR300 PSU

Thanks, I can't remember for sure what was in mine but I don't think it was an OZ4, possibly a 6X5.

Lawrence.
ms660 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 8:46 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.