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

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Reply
 
Thread Tools
Old 15th Aug 2019, 10:38 am   #1
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Post office test meter 12C

Hi there

I've been looking on the forum trying to find out something on this meter.

If anyone could shed a little light, I'd be REALLY grateful. Just bought it after reading what others had said on here about P.O / AVO meters.

This will be my first analogue meter
Attached Thumbnails
Click image for larger version

Name:	PO 12C.jpg
Views:	136
Size:	36.7 KB
ID:	188359  

Last edited by AC/HL; 15th Aug 2019 at 11:21 am. Reason: Image uploaded
Raptornet is offline   Reply With Quote
Old 15th Aug 2019, 11:52 am   #2
FIXITNOW
Octode
 
FIXITNOW's Avatar
 
Join Date: Feb 2007
Location: Ely, Cambridgeshire, UK.
Posts: 1,239
Default Re: Post office test meter 12C

There's a bit here on 12/B but not much data on most GPO test meters anywhere.

http://www.dustygizmos.com/arcpages/arctest.htm#GPO

12B/1 Multirange
FIXITNOW is offline   Reply With Quote
Old 15th Aug 2019, 12:03 pm   #3
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,851
Default Re: Post office test meter 12C

What did you want to know? General rules, start at the highest range and work down if needed, and avoid get the polarity wrong when testing DC!

Check and see if the battery/batteries have leaked. These designs are a little prone to damage as there isn't much stopping the leak spreading onto the circuit board.

Dave
The Philpott is offline   Reply With Quote
Old 15th Aug 2019, 12:32 pm   #4
AC/HL
Moderator
 
AC/HL's Avatar
 
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 7,350
Default Re: Post office test meter 12C

This version was based on the GEC Minitest, some others were AVO or Taylor based.
__________________
Bill, BVWS member
AC/HL is offline   Reply With Quote
Old 15th Aug 2019, 1:23 pm   #5
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

Thanks for the replies
I did wonder if manuals were available. Realise most analogue meters are pretty similar.

One thing I would love to know is when this was manufactured, 60s/70s?
Raptornet is offline   Reply With Quote
Old 15th Aug 2019, 3:44 pm   #6
Granitehill
Triode
 
Join Date: Mar 2019
Location: York, North Yorkshire, UK.
Posts: 25
Default Re: Post office test meter 12C

I've got one of these - I think mine was manufactured in 1973. The instruction plate on the back has the legend "12B R.P.B 73/5". I've no idea what R.P.B stands for, I'm afraid.
Mine is identical to yours, except for the panel lettering which shows "P.O. M.M-R No.12B". I can only assume yours is a later revision, since yours shows "No. 12C". I think the manufacturer was SEI (Salford Electrical Instruments - later taken over by GEC).

Should you need to get inside the meter, there are two screws concealed under the instruction plate. This is glued in place, so you will have to carefully peel this up with a thin blade. Double sided tape will stick it on again.

Nicely made inside - all I had to do was apply a wee bit of contact cleaner/lubricant to the AC/DC toggle switch and the track of the ohms adjust pot. It gets used most days, and is my first go-to for quick non-critical measurements. Accuracy is OK, but AC measurements are a bit out - it reads about 10% high on the 250 VAC scale.
__________________
John G4FDD
G-QRP 431
Granitehill is offline   Reply With Quote
Old 15th Aug 2019, 6:29 pm   #7
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,851
Default Re: Post office test meter 12C

Raptornet, did your purchase come with a leather carry-case? If not, once you've established the meter is working let me know the dimensions-

It's feasibleIi have a PO case that will fit it- you can have it for the price of postage.

(It's intended for a 12D/1 but the 12C may be the same size.)

Dave
The Philpott is offline   Reply With Quote
Old 15th Aug 2019, 10:16 pm   #8
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

It did come with a case, but it's seen better days and the clasp is bust
Raptornet is offline   Reply With Quote
Old 16th Aug 2019, 10:28 am   #9
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

BTW it works. Would it be wishful thinking that there might be a manual for this or a similar model?
Raptornet is offline   Reply With Quote
Old 19th Aug 2019, 10:34 am   #10
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

Finally cracked open the meter to look at the battery compartment. Oh boy, an Ever Ready B154 and Vidor HP7 sit in situ. The HP7 was just aweful.

Luckily the contacts were not eaten away. Have cleaned them down with alcohol.

Question, what is a 15v B154 and can I get a replacement?
Attached Thumbnails
Click image for larger version

Name:	IMG_20190819_101513.jpg
Views:	30
Size:	65.9 KB
ID:	188566   Click image for larger version

Name:	IMG_20190819_101519.jpg
Views:	39
Size:	48.8 KB
ID:	188567  
Raptornet is offline   Reply With Quote
Old 19th Aug 2019, 10:50 am   #11
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 13,329
Default Re: Post office test meter 12C

You can get B154 replacements (at a price) several vendors on Ebay for starters.

Rolling your own with a stack of button cells is another way to go.
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is online now   Reply With Quote
Old 19th Aug 2019, 11:14 am   #12
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

Fantastic! Don't know why I didn't think of using eBay. Managed to source one. Can't say I've seen a 15v battery before.
Raptornet is offline   Reply With Quote
Old 19th Aug 2019, 4:04 pm   #13
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,851
Default Re: Post office test meter 12C

Here's the case i mentioned

The thin strap is 'abbreviated' but the remains of it latch together.
The clasp works.
The thick strap must be so you can use the meter without taking it out of it's case.
It weighs 500grams (!) but it's so tough it won't need too much packaging.

interior- H a shade over 5"
W 3 and 3/4 inch
D 2 and 3/4 inch (plus the leads compartment)

Dave
Attached Thumbnails
Click image for larger version

Name:	DSC01356.jpg
Views:	28
Size:	62.4 KB
ID:	188594   Click image for larger version

Name:	DSC01357.jpg
Views:	26
Size:	72.8 KB
ID:	188595   Click image for larger version

Name:	DSC01358.jpg
Views:	22
Size:	59.9 KB
ID:	188596   Click image for larger version

Name:	DSC01359.jpg
Views:	23
Size:	70.3 KB
ID:	188597  
The Philpott is offline   Reply With Quote
Old 19th Aug 2019, 4:14 pm   #14
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,851
Default Re: Post office test meter 12C

Also 8 or 9 stitches have pulled at the top of the back, where they are under strain when the flap opens all the way. So serviceable but scruffy.
dave
The Philpott is offline   Reply With Quote
Old 19th Aug 2019, 5:46 pm   #15
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

Dave that's great, can I have it please? Looks almost identical to the one that came with mine, just a lot better nick. The metal parts on mine are rusted to hell.
Raptornet is offline   Reply With Quote
Old 19th Aug 2019, 8:35 pm   #16
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,851
Default Re: Post office test meter 12C

Yep! Will work out postage and do a private message to you.
The Philpott is offline   Reply With Quote
Old 20th Aug 2019, 11:12 am   #17
Raptornet
Triode
 
Join Date: Aug 2019
Location: Sheffield, South Yorkshire, UK.
Posts: 15
Default Re: Post office test meter 12C

Great stuff, can anyone tell me if there is a manual for these any place?
Raptornet is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 2:20 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 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.