Restoring the monster (1000-ZXL)

This is my repaired “to as new condition” 1000-ZXL.
I welcome myself into the “I Restored a Nak-1000 ZXL and survived” hall of fame.

These are the faults I found:

No meters.
Bad dynamics on meter after PP caps replacement.
Bad 400Hz tone (PP cap problem).
No FF, REW or PLAY, because of idler tyre.
High W&F, needed new belts.
Worn pressure rollers / guides, out of alignment.
Hardened grease, and oil spill all over mech.
Damaged (chipped) erase head.

These are the repairs I had to make:

Electronics:

Orange PP caps replaced in all boards.
Troubleshoot meter dynamics: Bad CMOS Switch on Display board was replaced.
Troubleshoot az. adjustment: Bad Flip-Flop on logic board replaced.
Full electronic calibration
Demagnetized Heads.

Mechanics:

Change idler tyre & belts.
Clean old grease, re-lubricate.
Fit new erase head, rollers, guides.
Full mech. alignment.

Cosmetics:

Wood cabinet sent for full restoration (no pics available yet).

The deck, as it arrived, was certainly less than perfect. Clean on the outside, but not working at all. I started working with the electronics, as the mech. seemed to work.

The Meters were not working, so I decided to replace the PP caps there. Some more caps were replaced in the BIAS, tone osc., rec. amp. and pb.amp. boards.

That cured the problem – partially. Left channel was behaving erratically, with bad dynamics. I traced the problem up to the IC601 (PD4066,Analog CMOS switch). I installed a new one, and the meter was back to life.

I used metalized axial polystyrenes 2.5% tolerance (available from RS). Some electrolytic in the signal path were bypassed with these too.

I had to work on the mech. afterwards. The previous owner had spread oil all over, and it was in a very poor state. The head assy. was painted with some grey paint, and looked terrible.

The erase head was chipped. Rollers and guides were very worn and dirty. I took it apart and started cleaning.

The mech. was slipping on FF, REW, and PLAY. A new idler tyre had to be put in place. On the classic Nak. transport it is a little tricky to replace, certainly, not for a rookie. All belts were replaced too.

The head assy. was very dirty. It had to be completely removed, cleaned and de-magnetized.

I could not source the needed parts, so I had to take my mech. to B&W in the UK for service. They installed all parts new, including a new erase head. They don’t take the 1000ZXL for service, but they agreed to do it on a bare transport. I got a flight into the UK (Thanks Ryanair for getting me there for peanuts), and took it to Worthing. In 2h my transport looked like this:

I know you can’t believe it, but YES IT IS THE SAME TRANSPORT, AND YES, IT LOOKS LIKE NEW!!

With new everything…

Including an erase head. After installed, and adjusted, I was getting 20-22KHz freq. response, FLAT (+/- 0.5dB).

Time to start to work on the front panel lights. A lot of them were bad, so I thought I could try to implement a LED kit. White leds are today widely available, so I sourced some from a eBay provider. 10$ got me a set of 50 White Leds + 50 500Ohm resistors.

As you can seen, they are a good match in size to the original bulbs.

Before installing the leds, mark your positive! LEDs as opposite to bulbs, need to have the right polarity.

PL28, which is the cassette lamp, can be installed as 2 LEDS, with a couple of resistors in paralell, for twice the illumination.

The result is a great illumination, but because the LED color temperature is greater than that on bulbs, the final color is more blue-ish, and less green-ish than the originals. Also, the 500Ohm resistor in the ABLE / RAMM panel, makes it a little too bright. Probably a 1K or 2K resistor would do better. The same chinese provider, has sets of “warm” white leds, I have ordered some. Also, 5mm LEDs would be a better fit for the keyboard. They have also been ordered. I will update the site when hey are installed.

When the deck was about ready, the auto-azimuth has started to fail. If I tried to auto az. it starts and stops in a tenth of a sec. The double flip-flop, IC512 (4013) responsible for triggering the Az. End signal on Logic board was faulty. I have replaced it and now it is working fine again.