Pioneer TX-9100 restoration

Back in the Summer of 2014, James Jamerson (from the fpm forum) very kindly donated a 9100 to me, having seen me raving about it to someone proposing to buy one.

On test it was a channel down, wouldn't come out of mono, had a very noisy tuner capacitor and the usual issues with pot/switch noise and blown lamps.
The only other issue was 40 years of dust and grime from storage in I guess lofts and garages, that sort of thing.

It cleaned up very nicely indeed and now sounds lovely with all issues sorted.

- Case cleaned and refinished with orange oil and wax.
- Black bezel around tuning face glass resprayed black as original paint worn away.
- Power supply recapped, plus rail decoupling caps on sub boards.
- lamps replaced
- pots/switches cleaned and lubed - this brought back the down channel.
- Alignment tweaked to allow correct stereo operation, discriminator circuit adjusted allowing muting circuits to function correctly.

- Tuning capacitor cleaned and lubricated. The symptoms of a dirty tuning capacitor are loud rustling and scratching sounds when attempting to tune along the dial. This happens because the multiple tiny pressure contact which need to make ground connection on the central brass rod inside the tuning cap get contaminated and make intermittent contact.
To resolve this, the capacitor needs to be thoroughly flushed with non-residue contact cleaner and then re-lubricated. To do this, place a cloth beneath the capacitor and literally drench the entire capacitor assembly in the cleaning fluid while rotating the capacitor moving parts. Repeat this process 3-4 times then allow to dry thoroughly.
You must use a non residue cleaner - NOT Deoxit, WD40 or other such cleaners which contain residues. Using such liquids will ruin the alignment. Be careful not to bend or disturb the capacitor fins.

After cleaning thoroughly, apply a TINY amount of lubricated contact cleaner such as Caig FaderLube to the tips of the contacts only. Dip the tip of a toothpick, cocktail stick or something similar and dab the contact pins where they make contact with the brass rod. See pic 8 below.

Some pics. Starting with the dirty interior, then onto the recapping, cleaning and the finished job.

A big thanks to James!


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Yummy

 

Your next project Rob?

http://www.ebay.co.uk/itm/Harman-Ka...383?pt=LH_DefaultDomain_3&hash=item35e6eef007

 

What is that gizmo screen on the left?

 

That HK730 is very tempting
The gizmo screen on the Pioneer contains the tuning station centre meter and signal strength meter.

 

I meant on the Harman. It looks like something from an old sci-fi.

 

Looks like a combination signal and tuning meter. Must have looked very futuristic in the 70s.