GPO Telephone 328F.

[davidhood999]

Hi, I wonder if anyone can help. I bought one of these phones from a carboot for not a lot of money so that I could convert and restore it, having successfully done the same with a BT 706 not so long ago.

I am new to the 'old telephones scene' and I thought I'd try my luck. I have replaced the line and handset wires accordingly, leaving the green wires out as per instructions on the British Telephones website; http://www.britishtelephones.com/pstconv1.htm#332.

The problem I am having is it will not dial out. I have pestered the poor man who's site it is, and both him and me are baffled as to why this is. I have also obtained another dial for this phone and tried that but to no avail. Does anyone have any idea how I can make it work? To complicate matters further, the handset did not work when it was wired according to the instructions, but when I moved the blue handset wire from T4 to T6 it worked perfectly. Hmmmmmm.

[Darren-UK]

Here is the original wiring diagram. I'd suggest comparing this against the instrument's current state and in accordance with the conversion instructions. Bear in mind changes of wiring colours, of course.

I suspect the instrument's been messed with prior to you obtaining it. Why did you change the handset cord? was a modern/non standard cord fitted?

Does the instrument work as it should for incoming calls and do you get the dial tone?

[BakeliteBear]

Darren is quite right.

Go back to the wiring diagram and thoroughly check all the connections. Do not imagine that you can make up your own version by trail and error!

A 328 should have a switch block - which complicates matters - and is often missing. If it is missing, just short out the terminals identified as going to the switch block i.e. strap T1 - T2.

Is there any sign that the wiring on the chassis has been messed around with? If not it will 99% certainly be down to incorrect wiring. Also check that no connections touch each other (shorting out). Check the dial loom (the 5 wires connecting the dial to the chassis) are all sound and have no internal breakages and that they are connected in the correct sequence Orange, Pink, Brown, Grey (or ‘Slate’ as BT boys would say), Blue and the right way around.

I would also say that the dial contacts might need adjusting, but if you have tried another dial that’s probably not the case.

When I can't get a phone to work (or anything else for that matter) a very good ‘trick’ is to put it away, sleep on it, and start again on a new day. It is amazing how a seemingly unsolvable problem becomes crystal clear on a new day!

Good Luck Chris

[Darren-UK]

Further to Chris's post, it wouldn't do any harm to check linecord continuity either. This is especially so if you fitted the PST plug yourself as they can be humbugs to fit correctly.

If the problem persists I'll post a picture of the wiring and strapping in my own 328 for you.

[davidhood999]

Hello,

Thank you all for your replies so far.

The line and handset cords were replaced as they were all damaged and very frayed.

The switch block is present and work correctly now that I have messed with the associated wiring. Im not sure if it is correct though. The dial tone is there, I can speak to people Ok, every thing works apart from the dial.

Re Darren-UK; Could youm please post that picture for me to copy when you get a minute? Also would you be able to include the back of the unit where there are two wires (for the bell on/off switch?) that had to mess with to make the On/Off switch work the correct way around.

In my unprofessional opinion, it does not look as if the phone has been tampered with. All wiring looms look original and do not look as if they are broken. I cant see that there are any shorts anywhere, unless I created a short when I messed with the back of the unit to make the bell On/Off switch work. To do this I moved one wire to the top right as opposed to the bottom, and inserted a strap from it to the next one. I did this after hours of messing around trying all combinations (!!)

Thank you all.

David Hood.

[BakeliteBear]

To eliminate the possibility that the dial might be at fault you might try fitting dial that you know does work, perhaps from your 706.

Also make sure there is no strap between 4 and 5 on the dial connecting block on the top of the chassis. If no dial was originally fitted these were strapped and if left in place it would prevent the dial from working.

When you say the dial does not work, are there any noises (clicking) when you dial or is it completely dead? Dials will not work if they are not set to the correct speed – although some exchanges are quite tolerant.

Posting some good quality pictures of your work so far would help - its a bit hard working in the dark!

Cheers
Chris

[davidhood999]

Hello BakeliteBear,

I will take some pics and post them to show what I have done as I am sure some of my descriptions must confuse people even more

When I dial I can hear clicking in the ear piece, like you would normally from a dial phone, but the dial tone does not stop and no number is dialed. I did put the dial from my 706 onto 328 (f) before buying another dial for it, and the same problem occured.

Thanks again.

David Hood.

[Darren-UK]

Attached is an image of my 328's terminal block. I've moved the wires out of the way as best as possible so the terminals are largely on view.

It might be worth mentioning that you should note carefully how each terminal is numbered as mistakes are easily made in that department:

Bottom row - 1 2 3 4 from right to left.

Centre row - 5 6 7 8 9 from left to right.

Top row - 10 11 12 13 from right to left.

Wiring as follows:

Linecord red to T9

Linecord white to T1

Linecord blue to T12

Linecord green to T7 (green is not used, T7 being merely a convenient park).

Resistor across T1 - T2

Strapping across T8 - T9 and T10 - T11 - T12

Handset is connected to T4, T5 and T6 with remainder of visible wiring being internal (see next post).

[Darren-UK]

The attached image shows the rear internal terminal block. Note the terminals are numbered vertically this time.

Of the two 'internal wires' shown in the previous image; it's blue to T11 and red/blue to T12.

[Darren-UK]

Handset plunger switch wiring.

The remainder of the wiring is awkward to photograph clearly, so your probably better orf checking such against the wiring diagram - especially that on the bell on/off terminal block. Hope these few posts help anyway.

[Gi4CZW Cliff]

Hello David, Does your telephone exchange accept line breaks as dial pulses, check by tapping the pulse out on the cradle switch. Also stop ( then let it return under your control ) the dial returning on " O " and watch the line voltage change as the the short/diss is repeated. Cliff.

[davidhood999]

Hello,

RE Gi4CZW Cliff; Im not sure what you mean, but my BT 706 works fine on our line so I asume that this one should?

RE Darren-UK; Thank for posting the images. I have wired mine up the same way as you show but to no avail. This is slightly different to how I had originally wired it when following the instructions on the above link.

I have looked at the original wiring diagram but I dont really understand what most of it represents so cannot really follow it. I am determined to get to the bottom of this so I have set about dissmantling the whole phone and putting it back togother in an effort to see if there is any broken wiring anywhere. Is this wise or am I making trouble for myself?

Everyone I have spoken to re this says there is nothing to go wrong with this model and that they are reletivly simple to convert. I BEG TO DIFFER SO FAR !!!

Thanks everyone so far, and please feel free to chuck in anything that you think may be helpful

David Hood.

[Darren-UK]

Don't worry. It's like anything else; conversion, repairs etc are simple once you've done them for the first time and thus have 'found your feet'.

My 328 was converted ages ago and, to be honest, I recall I just 'did it' without consulting any conversion instructions. Point is, it works fine via any socket ie master or extension, with or without other instruments plugged in simultaneously.

What David means is does your telephone service provider cater for pulse dialling as well as tone dialling. I think BT still cater for pulse dialling universally but Virgin, as I understand it, is patchy depending upon area and the original provider who they took over (Telewest, NTL).

[julie_m]

First, make sure that the dial is actually generating pulses.

With the phone disconnected from the line and the dial disconnected from the rest of the phone, connect an analogue meter set to a low resistance range across the pink and orange wires and watch what happens as you dial a digit. The meter should read short-circuit, briefly pulsing towards high-resistance as many times as the digit you dialled (ten for 0) as the dial returns to rest.

If you haven't got an analogue meter, use a simple test circuit with an LED, 470 ohm resistor and 9V battery. The LED should light up with the dial at rest, and blink off with the dialling pulses.

[BakeliteBear]

Originally Posted by Darren-UK

I think BT still cater for pulse dialling universally but Virgin, as I understand it, is patchy depending upon area and the original provider who they took over (Telewest, NTL).

I have heard this said many times, but have yet to find any UK domestic telephone line which does not support pulse dialling. I think this is actually a myth used to cover the fact that some restorers do not have the correct equipment to set dial speeds and the make/break ratio. I am happy to be proved wrong if anyone knows an actual exchange that will not accept pulse dialling.

Back to the question ... if you have swapped the dial over for one which works in the 746 I can't see that it is the dial at fault. I would still be suspicious about the dial loom and whether it has been connected in the right colour order at both ends.

Don't give up!

[teetoon]

Hi, sorry to jump in but had to reply to Bakelite Bear's comment about pulse dialling exchanges. I have been with TALK TALK for 3 years now, and earlier this year I noticed I could no longer use my dial phone in the shed to dial out. An easy test for this is just to hit the on hook button briefly (on any phone). If it returns to dial tone then your exchange line doesn't support loop disconnect anymore.
David.

[BakeliteBear]

Originally Posted by teetoon

I have been with TALK TALK for 3 years now, and earlier this year I noticed I could no longer use my dial phone in the shed to dial out.
David.

Rather than take this tread off track (it would be good if David could eventually fix his 328!) I will start a new thread to see if anyone else has a suppler that does not support pulse dialling. I am still fascinated to see if this is actually a real problem. If it is, I worry that it will do for vintage telephones what the loss of 'receivable' radio stations has done for vintage radio!

Chris

[Darren-UK]

As David says he successfully converted a 706 "not so long ago" and the instrument still works on his line, this won't be the cause of the problem. Perhaps my last paragraph in #13 was misleading in this respect.

As David's also changed the dial, I doubt that component is at fault either - unless the wiring is wrong.

Something's still nagging me about the linecord, especially the connections in the plug. Pesky things at times.

[davidhood999]

Hello people,

Here is the latest; I have tried another line wire and the problem still persists, I have also made another wiring loom to connect the dial to the main mechanism, but to no avail.

My next task I think has to be to check that every other wire is connected to the right place and going to the right place. However, I just cannot fathum the wiring diagrams out and wondered if anyone could shed some light on some things for me? The areas that I have difficulty knowing which are being refered to are highlighted in red and numbered for easy reference, and an image of my phone mechanism is next to it. If anyone is able to explain in laymens terms ie "number 2 is the big silver part on the left", then I would be a very happy chap.

I must point out that some of the wiring that you see in the pic is not as per instructions (as mentioned in previous post), this after hours of trying to make the handset work. It will not work in its correct wiring, it will only work wired this way Also the image was taken mid "fiddle" so some bits I have since noticed are loose. Theyre not loose when I test the phone. Just thought Id mention it

Thanks again.

David.

[davidhood999]

Hello everyone. I have been away for a bit as I could not log back into by account here for some reason, but have sorted my paqssword out again

Since I was last here I have worked out how to read the diagram (quite simple once you work it out eh?), and have followed it. I can now tell you that every wire is in its correct place. Bearing in mind I have tried another dial that I know works, but to no avail, and the wiring is correct, leads me to asume that the part marked on the diagram; COND MC No97, or the other part; COIL INDUCTION No27, is faulty. Is this a reasonable asumption?

Also just to add; I have used a second line wire that I know definately works, and I have made up another wire loom to link the dial but both excersises were fruitless.

Which if any of the two parts should mentioned should I start with by replacing?

Many thanks.

David.