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The 800 Colorfone


801/802 Problems & Fixes


by Denys Parker

In these Newsletters over the last year we have looked at the reasons why the Australian PMG's Department decided to design and control the manufacture of a new telephone in the late 1950's-early 1960's. This resulted in a worldwide search for an initial instrument to start from, BTM's 'Assistant', and the outcome, the Australian 801 'colorfone' introduced in 1963.

Now, you can test things in a laboratory and even do field trials, but nothing sorts out the weaknesses in anything the same way as installing it in quantity out here in the real world and letting the public use, and abuse it. This article will look at some of the weaknesses found in practice in the 801 and 802 rotary dial colorfones and the modifications used to correct them.

The Dials.
The fact that there were originally 3 different dials being used was in itself a problem. The maintenance man had to have the correct replacement or use one of the others and the corresponding adaptor number ring. Some dial finger plates split across when the countersunk retaining screw was tightened. One of the faults became very apparent in the late 1960's early 70's when I had to maintain a particular Ericsson ARD561 PABX. The circuitry of this PABX was such that the extensions did NOT have a recall button (Earth Recall) which allowed the person on an extension phone to transfer an existing incoming exchange call to another extension. The person on the first extension only had to dial the digit 1. This sounds good in theory.

One of the STC dials that we used had a problem with the impulse contacts. The silver of the contacts would go black and become "high resistance" and noisy and all one had to do was to tap the phone on the case and it would 'dial 1' and go into Recall. Even by accidentally touching the phone with some papers on the desk or closing the desk drawer would do it. The extension user often never realised what caused their conversation to be cut off. These PABX's were installed at large businesses so the customers got pretty upset. Our instructions were NOT to clean the contacts. The dial was to be replaced.

There were 3.5 Million dials in Service in Australia around 1970, 55% of which were estimated to be less than 5 years old. During that year 72,000 dials of all types were reconditioned in PMG Workshops at a cost of $108,000 plus all the costs of recovery and handling. A better dial had to be found.

A new Australian dial, the DMS, (Dial Multi Speed) was developed by AWA between June 1963 and June 1971. It still had the chaplets on it for the 801 telephone and was known as DMS-1. When modifications placed the numbers on the dial and not on the adaptor ring it was designated DMS-2. Further improvements to the governor resulted in the DMS-3, the last of the rotary dials. By May 1975 the only dial being supplied was the DMS-3.

The Case.
The 802 case could now be simplified, as no adaptor rings were required. (For further info, refer to an excellent article in May 2000 Newsletter by Bob Mills.)

The Capacitor.
If we look at the original printed circuit board used on all 801's and maybe even early 802's, the PCA1, we will notice a round canister which housed both capacitors. It didn't take too long to discover that, if there were parallel 801's installed, a conversation on one could be heard on the other without even lifting the handset. How embarrassing! This was caused by the proximity of the two capacitors in the same can. The modification was simple and entailed the use of two 40mm quick connect links by connecting RA to GS24 and RB to GS25 which short-circuited the receiver when the handset is hung up. Early PCA2's to 1967 still had the single can while those dated 1968 and later had the two capacitors mounted separately.


Click Suppressor.
Originally mounted directly on the rear of the 4T receiver, this was shifted to the later Printed Circuit Board, PCA-2B. (around 1978)

Printed Circuit Boards.
There were four in use, PCA1, PCA2, later PCA2B and finally PCA17 (around 1980). The PCA17 would take the 800 telephone on as far as model 806, the last one with a metal base and a mechanical bell. Some PCA17s have had the click suppressor removed or never fitted.

The Plugs and Sockets.
The pins and springs of the original 603 plug and 610 sockets were made of brass and suffered significantly from CORROSION. In the idle, on hook, not being used condition there is exchange battery on the line of nominally 48 volts DC. Combine this with some dust and Queensland's humidity and you get electrolysis and corrosion. This caused a high resistance noisy connection (HR) which eventually went open circuit. (O/C) The corrosion would travel up into the line cord from the quick-connector on the plug terminals necessitating the replacement of the plug, the socket and the line cord. The original sockets were flat underneath which held any moisture. Mounting the socket directly onto a brick wall caused moisture and salt from the bricks to condense inside them. The use of a flush-plate was then recommended.

Sometimes the subscriber contributed to the problem by supplying the moisture. The socket was mostly mounted on the skirting board in a room and it was around there that one mopped the floor or sprayed for cockroaches. The result was a telephone that was as dead as the cockroaches were supposed to be.

A number of modifications were tried. If the telephone wasn't portable (the plug made captive in the socket) then the male pins of the plug were sometimes soldered to the springs in the socket. Another method entailed the removal of all the pins & springs and the fitting of 3 'straps' or 'bands' which went across from the socket into the plug, which was thus made 'captive', and the cord quick connects slipped over that end of the straps. For years the technical staff in Queensland complained about the problems with plugs & sockets to Head Office in Victoria. They didn't have anywhere near the problems we did (lower humidity) and didn't seem to believe us.

The design of the plug/sockets and the metal used was changed a couple of times. I have some early brass 603/610 types, some marked 603N/610N with 6 short standoff feet underneath and with wide, silver coloured pins and the later 603M/610M type. I have a 1967 and 1972 light brown 610N socket (does anyone have a spare brown plug)? Ones with half circles around the lid screws (604/611) were for 'Permitted Attachments' such as FAX & answering machines, alarm or auto diallers, antique or decorator phones etc. You will notice the plug spigot or tongue & corresponding hole is wider and 'T' shaped on these to prevent the 'Permitted Attachment' being plugged into an ordinary 610 socket.

Take the cover off a 611 socket and you will notice a reversible spacer between each pair of springs. Reversing allows the springs to either make or not on withdrawal of the plug. This could allow through connection to the telephone on removal of the device from the socket.

I have a 603 plug dated 1970 with wide silver coloured pins in lieu of brass and others the same but marked 603N/610N dated 1972. I don't know for certain the meaning of the 'N'. Was it for 'New', 'Nickel' or 'Non corrosion'? Perhaps someone can shed some light on this.

The final solution involved the use of 'Monel 400' alloy, (this is similar to that used in our coins) and differently shaped plastic parts which reduced the retention of moisture and increased the distance of the insulating material between the conductors. They were designated 603M/610M. Some were probably on trial earlier as I have one dated 1972. I have records which say that from 1/7/1973, Transmission Products Pty Ltd were to supply the new plug/sockets 603M/610M at the rate of 85,000 a month, an incredible figure. In May 1975 these were in such short supply in Queensland that they were only to be used in portable services. All fixed 800's were to use the 'banded' or 'strapped' plug/sockets. You will note that the 1974 BRISBANE FLOOD was right in the middle of these two dates. The replacement of plugs/sockets and cords due to corrosion was our bread & butter fault for over 10 years.

The 605 plug had a normal width T shaped spigot and was the last of the plugs supplied as a separate replacement. This allowed it to be plugged into all sockets including type 611 (special attachments). The last plug of the 600 Series was the 606, a stubby thing permanently glued onto the line cord. Its equivalent socket was the 612. This was also smaller than all the older types and was designed with insulation displacement type terminals (requiring a Krone tool) and a clip-on cover. Most of the technicians in the field preferred the 610M with its screw terminals. After a short time the 612 was no longer purchased due to the low usage rates.

The Gravity Switch Plungers.
The original plungers were made of a clear plastic material. After some years it was noticed that these gathered dirt, possibly from static electricity, and would stick. In 1974 we were instructed to replace them with white plastic plungers PGS2, S311/68. There are only a very few 800's around now with the original clear plungers.

The Bell.
The main problem with the bell occurred when the 'phone was dropped. The inertia of the heavy coil (when the 'phone hit the floor) either moved the coil or broke one of its plastic mounting lugs and put the bell out of adjustment. Most customers wouldn't admit to having dropped the 'phone.

Mounting PBA-1 had the large bell coil by STC or AWA with clear plastic mounting lug ends. A much smaller AWA coil with 'RMA' on the coil and with white plastic end mountings on PBA-3 solved the problem. The mechanical bell was used until superseded by an electronic tone ringer in the 807 in 1984.

The Receiver.
The only thing that never changed, the 4T receiver.

Transmitters.
In 1975 we were requested to return all faulty transmitters to the store instead of disposing of them. This was so the carbon granules inside could be recovered because they were in such short supply. This situation could not be tolerated. Even so, the No13 transmitter remained the standard until 1984. In the meantime, the Telecom Research Laboratories produced a specification for an electronic transmitter that would directly replace the No.13. This specification required the new transmitter to:-
Fit into the 800 series handset and allow for the anchoring of the handset cord.
Operate correctly in a telephone in parallel with a second telephone fitted with a No.13 transmitter.
Improve the 800 series telephones' transmission performance.
Be as robust electrically as a No.13. (withstand voltage surges etc)
Be independent of the effect of feed current on transmit performance.

A schedule was issued by Telecom in 1977 to allow private manufacturers to submit tenders and prototypes for evaluation.

Soon after, STC produced limited numbers of a transmitter, which looks identical to the 4T receiver, except it is not marked 4T. I had a couple on field trials in Brisbane around the early 1980's. They were marked STC (with a date from '78 to '80) 132108 on the rear and the kit came in a cardboard box marked 'CONT 56212, Qty 1, 311/76'. It consisted of the transmitter, a plastic ring and an adaptor cup (a modified RAO-1) with a metal clamp to anchor the cord. There were only a very few here on trial and I was told not to lose them. I never did.

In the end, the tender submitted by NEC of Japan was successful. The contract stipulated that Telecom be provided with samples and full design details so Telecom would "own" the design. The result was the 20E electronic transmitter. NEC and AWA were awarded manufacturing contracts and between them were to produce 683,000 type 20E transmitters between December 1983 and June 1984. Philips Australia were also involved by developing an equivalent integrated circuit to that developed by NEC. As usual there were some modifications along the way. The bodies of the early Japanese made NEC ones I've seen are nickel plated plastic. (This acted as a radio interference shield.) The later Australian made NEC ones are of white plastic. The terminal lugs were then shifted from being in the centre 180 degrees apart to close to each other on one side on the later again cinnamon coloured ones. The front covers also varied in time from having 3 holes to only one. I haven't seen any with AWA marks on them, only NEC.

The cost of the 20E was about three times that of a No.13 but Telecom hoped that the long term advantage of savings brought about by reduced maintenance visits would cover this. I wonder if it really was worth it. Only 4 years later in 1988, the introduction of a new Australian designed telephone, the T200, ensured the end of the 800 Series of telephones.

For a long time the 800 Series has been somewhat neglected by collectors. They were the 'standard' for the 25 years from 1963 to 1988 and there were many modifications and models. More than enough to keep me occupied with a few more articles.

Information for this article was gathered from various Customer Equipment Maintenance Handbooks, Information & Staff Bulletins and Newsletters and other official PMG and Telecom journals and Publications. (The sentences prior to are the Author's personal observations.)

Denys Parker



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