Ampex 2163 Reel to Reel Belt Replacement

[DMcMahon]

Replaced the old 3 pin mains plug with a new plug.

At a quick glance the mains cable looks like a flat (quite large) twin core, it is one of those USA cables where the green earth/ground wire sits in-between the insulation of the 2 black live and neutral wires.

David

[DMcMahon]

While previously rebuilding the unit after recovering the broken headphones adapter had another closer look at the decomposing blue rewind tyres on the yoke assembly.

The design of my 1163 with O-rings on the yoke assembly is slightly different, the O-rings fit in a groove on the wind drive pulley but on the 2163 it looks like there is no groove but there appears to be something under the tyres. Also on the 1163 the play clutch piece is flat as opposed to conical on the 2163.

Both service manuals for the 1163 and 2163 show and list identical parts for both units namely the tyres and conical end shaped play clutch so my 1163 has some different parts.

When I come to replace the belts on my 1163 I will try the yoke assembly from the 1163 in the 2163 to see if the various tape transport issues previously seen are any better with yoke assembly with O-rings.

David

[DMcMahon]

After checking all the head wiring connections, found that the Forward Play right hand channel of the combined Playback/Record is open circuit, so explaining why no right channel playback signal with hum only.

A real nuisance, will be difficult source a compatible head.

A good reading for these PB/Record heads is around 56 Ohms / 140mH.

In addition to the 4 pins on the head for the system wiring there are another 4 pins, 2 pairs of 2 being linked together figure of 8 with fine wire, the wire is slightly potted to the head.

Measuring from each of these pins to its adjacent system connection wire pin gives a reading of around half of the normal head reading, so looks like there are 2 windings in series for each track of the head.

On the open circuit head one of the 2 separate windings is good so planning to rewire the head across the single winding (for the right channel) to see what happens.

Because disturbed a lot of connections have put it all back as standard to make sure have not created any new problems, it is as before, i.e. good playback on both channels on reverse playback and good playback of the left channel only on forward playback.

Next will check out recording to see if it works.

David

[DMcMahon]

Recording works fine on Forward record left channel, nothing of course on playback of forward right channel recording because of the dead head.

Recording works fine on Reverse record left channel but nothing on the right channel recorded (erase works).

Difficult to work out why no reverse right channel recording, getting good record signals on the VU meters and also monitored on headphones/line outputs.

Would be nightmare to try and monitor signals at the amplifier, first will lift up the heads assembly and see if record signal is getting through to the heads for both channels.

David

[DMcMahon]

While checking out playback and record the tape transport operation started getting really bad, with loose tape rapidly coming off the Supply spool and getting tightly wrapped behind the supply spool carrier.

This was intermittent and very difficult to see what was actually occurring but occurred during rewind and fast forward wind plus also during forward and reverse play.

Still suspicious of the decomposing blue tyres so will fit the Yoke assembly from my 1163 (which has O-rings as opposed to the blue tyres) in place of the 2163 Yoke assembly to see if any different.

I have to remove the Yoke assembly anyway (or at least do a big strip down) from my 1163 in order to replace the drive belts on my 1163.

David

[DMcMahon]

Removed the Yoke assembly from my 1163 and fitted it to the 2163.

Initially the tape transport worked very well but after a while it started playing up intermittently as per Post 25. The 1163 Yoke assembly has O-rings for play drive and the 2163 has the decomposing blue tyres for Play drive. The fact that the 1163 assembly is giving the same results I think means that the decomposing tyres are not part of the problem.

While trying to work out what was occurring the tape transport stopped working all together and I found that the Supply spool carrier (turntable) had no drive due to a small grub screw that locks the spool carrier to the reel table shaft had loosened.

There is a groove in the shaft that initially I thought was a wear mark but by looking at the other shafts (in the 1163 & 2163) it is a machined groove to take the point of the grub screw.

Hopefully this is the root cause of the various previous tape transport issues, will refit and retighten the grub screw.

[DMcMahon]

After refitting the Supply spool carrier and making sure its securing screw was really tight the tape transport all worked well with the Yoke Assembly from my 1163 fitted.

Removed my Yoke Assembly and fitted the 2163 Yoke Assembly back in and the tape transport all continued to work well. But now some time later Forward Play is intermittently very noisy, really difficult to see why but am still somewhat suspicious of the decomposing blue O-rings.

Need to fully assemble the unit and get it back to my friend (the owner) very soon for him to try it out, so probably at this stage will not be able to resolve the noise issue.

David

[DMcMahon]

After more exercising, the intermittent knocking sound during Forward Play has become very regular and now only runs for a few seconds when the motor then stops, Reverse Play still works fine.

The Forward/Reverse Play direction somehow is done by the switching of the Forward/Reverse switch changing the rotation direction of the motor.

The PDF copy of the Service Manual I have is poor quality and the Motor Control circuitry on the schematic is extremely difficult to make out properly so somewhat difficult to see how the motor is actually reversed.

Initially I was thinking that it most likely is an electrical problem but have just seen that with no tape loaded I cannot get Forward Play to fail but as soon as tape is loaded Forward Play then fails (motor stops running) after a few seconds, so that is confusing.

David

[DMcMahon]

Found a spring that connects the Reverse solenoid shaft to the motor Play/Reverse switch linkage was disconnected at one end, after a little strip down and reshaping the end of the spring refitted spring (not easy) but no difference afterwards to the motor stopping or the knocking sound.

After more checks conclusively proved that the motor stopping is due to the horrible sticky blue decaying O-ring on the Take Up side of the Yoke Assembly, this drives the Take Up reel table in Forward Playback.

Pretty sure it is also the cause of the knocking. It was creating so much stiction between the reel table and the roller on the Yoke assembly that it was stopping the roller and the drive belt from moving which in turn was stopping the motor.

Previously was not even sure it was an O-ring as it looked totally different from the black O-rings on my 1163 machine but after scrapping and cleaning off (not easy) the blue mess can see that roller part has an O-ring groove with raised side walls on the shaft the same as my 1163

I have some small O rings, just need to find them. Hopefully will have a size that fits and works. Once I get Forward Playback working I then will replace the Supply side 0-ring, even though Reverse Playback currently is working the O-ring is in the same flattened/spread out sticky mess so would only sooner or later cause similar problems.

David

[DMcMahon]

Found my small spare O-rings (a Lidle set) none quite the right size but I fitted one which was a bit larger and it is working very well, no more knocking in Forward Play.

Also replaced the Supply side O-ring and it also is working well in Reverse Play.

Still wonder if they are supposed to be O-rings. The O-rings in my 1163 look very good condition so possibly they have been replaced at some stage. On the parts list they are called "Tire" and on the drawing it is possible to see them as square sectioned.

David

[DMcMahon]

A few days back I saw a Service manual for the 2000 series on eBay at £0.99 Buy it now, seemed too good to be true so I brought it. There was only 1 photo showing the front cover page and no real details about it, so I thought it must be an incomplete copy or in a terrible state.

It arrived today and is a complete original very detailed and in pretty good condition, an absolute bargain. To get the same manual from the USA is > £30 plus hefty postage.

David

[DMcMahon]

Rechecked the Playback and Recording problems referenced in Post 23 & 24.

Found that Forward and Reverse playback of an existing stereo recording only gave good results on the left channel with the right channel having a very quiet recorded signal with hum present. For Forward playback saw the same previously and diagnosed as the Forward Playback/Record head having one of its 2 series windings (on the right track) being open circuited.

Bypassing the open circuit head winding then gave good stereo forward playback on both channels (of existing good recording).

Investigating the reverse playback fault of bad right channel (which previoulsy had been good) revealed that the reverse Playback/Record head now had the same fault as the forward head in that one of its 2 series windings had gone open circuit (strange for 2 heads to develop the same fault over short time period). After bypassing the open circuit head winding now stereo reverse playback is good for existing good recordings.

Checking new recordings found that the right channel playback is low volume with hum (for both Forward and Reverse Playback) presumably once again due to the bad head windings but by switching the playback mode to Mono 1 (which sends the left channel to both audio channels get very good playback sound in both channels so is a good workaround.

David

[DMcMahon]

Tested the automatic threading of the Take Up spool using the special black metal automatic take up spool.

Works very reliably on speeds 7 1/2 and 3 3/4 ips, struggles big time on 1 7/8", the user instructions for the automatic threading do not specify what tape speed to use but do say that it may be necessary to hold the 1" of tape that sticks out of the top of covers to aid threading but I never tried that.

The user instructions say that the 2 covers over the auto threading spool should always be left fitted. Not sure why (apart from maybe looking tidier) as it works fine with the covers subsequently removed after auto threading.

Although I must admit not being used to open fronted/pancake type spools it does look a little precarious with all the tape on the take up spool fully visible.

David

[DMcMahon]

Tested auto reverse which works very well. The machine provides a 20Hz tone which you record at the tape position where you want the tape play direction to auto reverse.

Could never get this facility to work on my 1163, I think now that probably I was doing the required procedure incorrectly, as the documented procedure at first read is not clear/is confusing. Will try it again on the 1163 now I know how to do it properly.

Did some more recording tests, found that if I boosted up the right channel record level signal (by adjusting the right channel record level control) by at least 2 units on the VU meter compared to the left channel, could achieve a pretty good stereo playback of new recordings, much better than it previously was and negating the requirement to switch the playback mode to Mono1 which was required to get good playback level on both channels.

Returned the unit to my friend (the owner) and demonstrated its operation, he is very pleased with it. He played it back through a lovely looking Fisher receiver with some big speakers, it sounded really good.

David

[ben]

That's some work you've put into this, David! Good to see it paid off.

[DMcMahon]

Interesting machine, somewhat different from many others, quite a challenge at times.

Even though I got inside the amplifier chassis to do switch and potentiometer cleaning, luckily never had to do any fault finding or set-ups in the chassis, everything in there is crammed and would be very difficult to work on.

David