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 Telephony and Telecomms

Notices

Vintage Telephony and Telecomms Vintage Telephones, Telephony and Telecomms Equipment

Closed Thread
 
Thread Tools
Old 23rd Sep 2014, 5:53 am   #1
Ryan_1993
Hexode
 
Ryan_1993's Avatar
 
Join Date: Sep 2012
Location: Yorkshire, UK.
Posts: 329
Default Bakelite 328 Conversion problems

328 series problem after conversion

Hello all,

I just got a 1944 328 series Bakelite Telephone in outstanding condition and have converted it.

I have found a couple of issues though.

Firstly, after you unplug it and then plug it back in and pick up the receiver I get no dial tone, just a faint electrical buzzing through the receiver. When the bell rings and you pick up to answer all is well and it works. I have to press the plungers down multiple times in order to get a dial tone to come on to dial out.

The dial is also extremely crackly and won't register any numbers being inputted, just crackles all the time, bizarrely the dial wasn't connected to anything inside the phone until I wired it, anyone know why that is?
Ryan_1993 is offline  
Old 23rd Sep 2014, 6:41 am   #2
ThePillenwerfer
Octode
 
ThePillenwerfer's Avatar
 
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
Default Re: Bakelite 328 Conversion problems

Sounds like dirty contacts and/or a loose connexion. These certainly need ruling out before investigating deeper.

- Joe
ThePillenwerfer is offline  
Old 23rd Sep 2014, 8:02 am   #3
Ryan_1993
Hexode
 
Ryan_1993's Avatar
 
Join Date: Sep 2012
Location: Yorkshire, UK.
Posts: 329
Default Re: Bakelite 328 Conversion problems

Thanks for the reply What would be the best way to clean it's internal contacts? Some sort of electrical contact cleaner?

I think what I am worried about is if it's an induction coil or something which is failing.
Ryan_1993 is offline  
Old 23rd Sep 2014, 8:21 am   #4
dagskarlsen
Heptode
 
dagskarlsen's Avatar
 
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 640
Default Re: Bakelite 328 Conversion problems

Quote:
Originally Posted by ThePillenwerfer View Post
Sounds like dirty contacts and/or a loose connexion.
This, and the contacts in the hook-switch would be the first I would look at.

Simple cleaning: take a piece of paper, wet in alcohol, and slide it between the closed contacts, (alchol, meths, isopropanol, methanol...)

Dial tuning are a little tricky, but usually not needed.

dsk
dagskarlsen is offline  
Old 23rd Sep 2014, 11:02 am   #5
Ryan_1993
Hexode
 
Ryan_1993's Avatar
 
Join Date: Sep 2012
Location: Yorkshire, UK.
Posts: 329
Default Re: Bakelite 328 Conversion problems

The dial operates very smoothly although not sure if I wired it up properly as It wasn't connected when I took the phone apart and so took the dial cabling out of an old broken 746 I had laying around and did it from memory. Do you know the order the wires should go for the dial?

I have methylated spirits would this work as a sufficient cleaner?

Thanks
Ryan_1993 is offline  
Old 23rd Sep 2014, 12:21 pm   #6
Dave Moll
Dekatron
 
Dave Moll's Avatar
 
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,118
Default Re: Bakelite 328 Conversion problems

Have you looked at the wiring diagram at http://www.samhallas.co.uk/repositor...0000/N428.pdf? Does that help at all?

Using a mechanical multimeter set to resistance, you should be able to identify terminals 4 and 5 (the dialling contacts), as turning and releasing the dial with the meter connected across them will cause the meter needle to vibrate as the contacts make and break.

Having established these two, terminal 3 can be identified as being shorted to terminal 4 while the dial is off-normal. In this state, terminals 1 and 2 will be shorted to each other as well, but not to anything else.

Having identified the five terminals on the dial, wire them up as instructed in the diagram.

I hope this helps.
__________________
Mending is better than Ending (cf Brave New World by Aldous Huxley)
Dave Moll is offline  
Old 23rd Sep 2014, 12:39 pm   #7
ThePillenwerfer
Octode
 
ThePillenwerfer's Avatar
 
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
Default Re: Bakelite 328 Conversion problems

Meths'll do fine.

Dial connexions shown below.

- Joe
Attached Thumbnails
Click image for larger version

Name:	Image1.jpg
Views:	90
Size:	37.6 KB
ID:	97930  
ThePillenwerfer is offline  
Old 23rd Sep 2014, 1:47 pm   #8
dagskarlsen
Heptode
 
dagskarlsen's Avatar
 
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 640
Default Re: Bakelite 328 Conversion problems

Yes methylated spirits are great.

The pulsing dial contacts (normally closed) are the really important contacts, te other ones are mainly to suppress noise.

dsk
dagskarlsen is offline  
Old 23rd Sep 2014, 5:34 pm   #9
Ryan_1993
Hexode
 
Ryan_1993's Avatar
 
Join Date: Sep 2012
Location: Yorkshire, UK.
Posts: 329
Default Re: Bakelite 328 Conversion problems

Update:

After a total clean and "blow" with an SLR bulb blower, the phone is working flawlessly. I found the problem, there were two tatty wires which connect the hook switch touching each other, I used a screw driver to bend the solder away from one another and all is well.
Ryan_1993 is offline  
Old 23rd Sep 2014, 6:09 pm   #10
ThePillenwerfer
Octode
 
ThePillenwerfer's Avatar
 
Join Date: Mar 2011
Location: Sheffield, South Yorkshire, UK.
Posts: 1,453
Default Re: Bakelite 328 Conversion problems

Jolly good.

- Joe
ThePillenwerfer is offline  
Old 24th Sep 2014, 10:00 am   #11
mike_newcomb
Rest in Peace
 
Join Date: Apr 2012
Location: West London, UK.
Posts: 665
Default Re: Bakelite 328 Conversion problems

Hi Ryan,

how about some photos please.

Regards - Mike
mike_newcomb is offline  
Old 3rd Oct 2014, 8:49 pm   #12
Ryan_1993
Hexode
 
Ryan_1993's Avatar
 
Join Date: Sep 2012
Location: Yorkshire, UK.
Posts: 329
Default Re: Bakelite 328 Conversion problems

Hello, here is a phone of the telephone.
Attached Thumbnails
Click image for larger version

Name:	Photo 26-09-2014 3 02 55 pm.jpg
Views:	113
Size:	83.2 KB
ID:	98318  

Last edited by AC/HL; 3rd Oct 2014 at 10:37 pm. Reason: Image rotated
Ryan_1993 is offline  
Old 3rd Oct 2014, 8:57 pm   #13
dagskarlsen
Heptode
 
dagskarlsen's Avatar
 
Join Date: Jan 2008
Location: Hakadal, Norway
Posts: 640
Default Re: Bakelite 328 Conversion problems

Looks great!
You have a nice one there!
dsk
dagskarlsen is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 3:45 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.