atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 1A2 and some old WECO stuff

Two days probably if I focus solely on this. But I want to enjoy the process. Now I have a dedicated space for this type of repair, so no need to create a mess at my regular desk

Some of more sweet stuff on my table in a new phone lab:

Revox A77 reel-to-reel stereo tape recorder made on Feb 15, 1973. This is to make a repair work on the phones more enjoyable.

This is a nice piece of Hi-Fi equipment with very good Swiss engineering inside. All Audio elements (left, right playback amplifiers, left and right record amplifiers, input amplifier, relays boards, oscillator, etc.) are made in a form of WE 400-type line cards: they are modular and inserted into similar multi-pin connectors on the backboard. So any trouble can be easily traced and corrected in minutes by replacing the cards.



I actually have now two of them (I always prefer to have a duplicate item for a good thing, just in case).

For these reel-to-reel guys - this IS the aftermarket! All our 1A2 rare items prices have nothing to do with what these guys pay for Revox devices and accessories. Not to mention WE audio electronic tubes - those cost an arm and a leg.

Ah yes! I have access to an old Sony 7.5" reel-to-reel at my Church. The drive belt must be stretched as the speed is off. The felt pressure pads for the tape heads are worn off and all three heads must be worn by now.

Sadly, nobody really fixes them anymore, and, tapes are long gone from the market. There is a box of tapes I can try to play as time allows.

For Revox a service manual is available for download from the manufacturer, plenty of parts on eBay, even the special kits with new variable resistors (trimmers) sets, transistors, capacitors, etc. This one has no belt (except the one for mechanical counter, which is not a critical application) - this is a 3-motor direct drive machine, i.e. the tape moving shaft and both reels are set directly on the motor shafts with no gears or belts transmission. I've cleaned and re-oiled the so called capstan motor (this is the one moving the tape at regulated precise speed) and it works well. This one utilizes semi-professional heads - they are huge in size and I believe have a good resource for wear off. And there are plenty of masters who fix them, upgrade them for a very good money. But I prefer to do it myself.

P.S. The 1/4" tape is still available (new one) since there are still many professional studious who prefer to use the classical non-digital technology. Old tapes are indeed no good - they deteriorate and start to produce an oxide dust which is all over the place.

I plan to use one of these machines for recording the telephone conversations (conference calls) at reduced speed of 3 3/4 inches per second, so will have in total ~16 hours capacity on one 10.5" reel with 1100 m of tape (because of 4 tracks available for monophonic recording). Will need to tied it up to a WE telephone - not sure if it should be a direct connection or via some sort of isolating transformer (like in WE 107B loudspeaker). Probably Arthur knows it...

A NOS NIB Precision Components 4A speakerphone has arrived yesterday. First impression was negative, since it is not a 100% reproduction of Western Electric 4A as I expected from pictures.

The major differences are:

1) Front panel of PC-108A loudspeaker is made of painted grayish-tan metal, not a sand-blasted aluminum like WE 108A



2) "OFF" an "ON OR QUITE" designations on the PC-680A transmitter are engraved in plastic and filled with black paint, not a double molding item from WE.



3) The red LED cap is attached to the stationary transmitter cover, not to the LED board itself. And the LED is not typical WE rectangular LED with lens, but a simple cheap LED. LED goes off when the ON OR QUITE button is depressed, so there is no visual indication of speakerphone being active while on mute (with coin technique, or I actually use a paper clip from metal wire with PVC cover not to scratch the plastic). On the other hand there is a clear indication that the microphone is deactivated, so this is actually good. Stationary cap has a factory installed shielding from a copper foil strip to protect the volume control variable resistor from RFI when user touches the wheel.



4) Better not to look inside - what you see there will resemble that this thing was designed and made in a garage. 4 PCBs are screwed to a thick pieces of transparent Plexiglas on both sides and it looks like it was cut manually by a hand saw and drilled with a accu screwdrver. BUT there are no flexible PCB there connecting the 3 main boards, which is the most thin place in WE 108A design. So chances are it will survive aging better than WE 4A.

But once I have connected that to the system my opinion has changed:

The sound quality is very good on both sides, specifically:

1) there is absolutely no hum from 18 VAC, which was the issue with original WE 4A whta made me to change it from 18 VAC from transformer to a filtered DC power supply.

2) transmission from the microphone is also very good with no hum or distortion.

All in all, because of the sound quality this item from Precision Component receives an approval for use in my 1A2 system.

One comment to all WE 2872 Touch-A-Matic users:

DO NOT connect your TAM power to the system voltage from the KSU. One of the sides of power supply within the TAM has a jump wire to a phone line (T or R side, not sure).

So the transformer 13.5 VAC coil should be a true isolated (free floating) coil. Otherwise it can cause issues within the system.

Note that the area on the TAM faceplate, just above the TT dial, is a perfect spot to mount the 4A transmitter unit, using double-sided tape. It keeps the transmitter from using extra space on the desktop, and its location is always obvious.

Hi Arthur, you gave me an answer to a mistery which bothered me for a long. I’ve almost bought 2 faceplates for TAM, but stopped when I saw the pictures: both were drilled in that area above the dial. I couldn’t understand who would drill it there and why. Now I see that most probably those were from TAMs with transmitter screwed above the dial.

But I’d like to keep it simple and in two separate parts. I like to move around while at desk, so I place the transmitter in different locations depending on if I present something from my computer or just lean back and participate occasionally in the conversation.

I used to work at the radio station many years ago. Since that time I automatically place any microphone I use into perfect location in terms of distance and direction of voice. This is uncontrollable.

And for my favorite telephones (and TAM is definitely the one, second being black WE 564 which started my whole collection) I always have enough space on the side extention to my desk. It is lower level vs. main desk, so it can’t be used for anything else.

As Confucius say: Holes bad. Tape good. Velcro® best.

I worked 6 years for 3M. I would say VHB is the best. Or Command for removable bond.

P.S. I’ve got it today - pink beauty 564. Hope it will come safe. I will share with you. This baby will require a lot of hydrogen peroxide and sandpaper, but I know beneath she’s a real beauty.