Ferguson 3440 Check Out

[DMcMahon]

A 1973 Combined 8 Track Cartridge Player with AM/FM Radio, originally would have had a pair of 8 Ohm external speakers but they are missing.

Mainly interested in the 8 track player, if the radio subsequently has problems then I will do a new thread in the Radio section.

It was sold as "Not working/Does not switch on".

Externally cosmetically reasonable condition for its age, the mains cable was very sticky and grubby looking so cleaned that up somewhat.

With the front panel On/Off switch switched on, measured the resistance across the Live and Neutral pins of the 3 pin mains plug at 88 Ohms. The schematic shows the mains transformer as 96 Ohms, so looks like have got a good primary winding through the internal 0.5A mains fuse (F1) and also that the plug fuse is good.

So assuming that mains transformer secondary winding is OK then at minimum with power applied should see the 4 scale lamps light up when radio is selected or if Tape selected should see one of the 4 channel lamps light up.

Opened up the mains plug and replaced the ever present 13 fuse by a 3A.

Slowly powered up from Variac, apart from fairly normal current drain on the Variac all appeared dead, no lamps lit on the 3440.

But when the function switch was switched to MW (Medium Wave) and volume turned up (headphones connected) was able to tune at least 3 strong radio stations with good sound on both channels, balance, treble and bass controls all working. So looks like main electronics are functional, that is better than expected.

Investigating why no lamps lighting up found that there is a dodgy single pole 2 way switch S3. This is the switch that is actuated when the tape cartridge is pushed in. With tape out the switch should switch 13V to the 4 scale lamps and with the switch actuated the switch then should switch the 13V through to the tape player motor and tape electronics.

Found that could intermittently get the scale lamps on when probing the switch contacts and with switch actuated could get intermittent tape motor rotation once again when probing the switch contacts.

Measuring the switch contacts resistance wise both switched contacts are high resistance, sometime open circuit. Have removed switch and will attempt to look inside the switch (will need to drill out rivets that hold it together) to see if anything can be done, but may well need to get a new switch.

David

[Station X]

That looks like a standard microswitch. I used to think they were trouble free, but now I know better!

[DMcMahon]

Yes looks fairly standard, I think I might have a possible donor (if required) on an old spare (used) electric shower.

David

[DMcMahon]

Switch dimensions very similar to the standard V3 push button microswitch dimensions.

David

[DMcMahon]

Found my old electric shower but unfortunately its 2 microswitches are only SPST. The switch symbol on the switch shows it as a SPDT but there is no contact arm connection to the NC (Normally Closed) contact (physically or electrically when measured to the common contact).

Drilled out the rivets on the old S3 switch and took the top off. Its contacts are visually switching but very poor contact electrically, will try cleaning the contacts. The switching actin feels very flimsy/weak, have ordered a new switch as back up if cleaning the contact does not help.

Linked out the switch wiring to power up the tape section. The capstan motor runs and the head moves up and down when the track select solenoid is energised when the manual track/channel push button is pushed and the appropriate track/channel lamp lights up.

Wil try a tape later, first need to clean up the head and the capstan shaft that are really dirty looking.

David

[DMcMahon]

Cleaned head, capstan shaft and general area, all pretty dirty. Lubricated the track selection mechanism.

Tried playing a tape and when tape cartridge pushed in it stopped the capstan shaft from rotating, capstan rotates fine with no cartridge. Manually rotating the capstan shaft it does feel stiff.

Added a tiny drop of oil at top and bottom bearings of the capstan (know that they are probably sealed bearings). Now the tape will play basically OK, it is possible if the cartridge is pushed in fairly hard from its normal in position to slow down even stop the capstan shaft. Later will have to lift out the tape deck to check out the drive belt.

Playback sound from the tape is quite reasonable, some times the left channel is lost or has lower volume, depending upon the placement of the cartridge as it is pushed in.

With the volume control turned fully down so no sound from the tape or radio there is a noticeable hum on the left channel, this may take some tracking down.

Not yet attempted cleaning up the contacts on the microswitch.

David

[DMcMahon]

After a bit of a struggle partially removed the tape deck so as to see/access the drive belt.

Initially thought it looked OK but from close examination it is somewhat slack. With it running and a little pressure applied to the flywheel or pushing in the tape cartridge hard, capstan shaft/flywheel stops rotating with the motor pulley spinning away OK in the slack belt.

Somewhere I have a stash of flat drive belts but most if not all are smaller ID size.

Removed the flywheel and cleaned/regreased the top and lower bearings, they are just Phosphure Bronze bearing sleeve/bush type.

David

[DMcMahon]

Found my stash of flat belts but largest ID one not really large enough but have fitted it and it looks like it may be OK. Need to re-assemble and fit new microswitch and retest.

David

[DMcMahon]

Installed new micro switch, its pinout was physically different compared to the old switch so had to transpose the wires around.

David

[DMcMahon]

Retested tape operation OK but as before still intermittently losing the left channel, before it appeared related to the tape cartridge insertion placement but now not sure if that is a contributor. At same time AM radio both channels are good but FM also appears to lose the left channel (am using my finger touching the FM aerial input screw to get FM tuned reception).

Also as before with the volume turned down (so that music does not mask the hum) there is a noticeable hum, maybe stronger on the left channel, I am wondering because I am listening on headphones whether I could maybe being over critical.

With have to have a look on the scope to try and work out why the left channel is disappearing and see how bad the hum level is and trace the source.

David