Nak BX-125 azimuth adjustment?

[TDWesty]

I brought my old BX-125 back to life last night with a new idler tire, but the azimuth seems to be way off after many years in storage. The left channel is about 20db down from the right, both on existing tapes, and newly recorded material. Is there a guide somewhere describing the adjustment procedure? Other possible causes?

Thanks.

[valveitude]

Unless the unit has been jostled/vibrated fairly heavily, it is unlikely azimuth is the problem..this is a mechanical adjustment. Bad head alignment produces a loss of treble more so than level (unless it's grossly out of whack).

I'm not familiar with this model, but if it has a mechanical record/play switch, this would be the first place I would look. Pop the cover and look for a long skinny metal can on the PC board that has a mechanical connection to the transport (stiff wire or ribbon typically). If it does, hose it down with a good contact cleaner, and work the heck out of it (LPS 1 would be my choice). These things have a zillion copper clips that ride back and forth on a metal rail. If it has been sitting long, the clips/rail have oxidized.

If that isn't the problem, the next most likely cause would be a failed cap.

-Casey

[TDWesty]

I'm listening to it right now, and I think you're right - I took a stab at the azimuth and it made little difference - I could make it worse in each direction, but not better. Now that I think about it, this problem may have been audible when I boxed it up about 6 years ago. I seem to recall many of my tapes starting to sound off, and I assumed they were just getting old (most are from 1987-90). So perhaps it is a cap or two gone bad. Another clue is a high freq squeal within the first few minutes of testing last night, which now seems to be gone.
Even with the left channel problem, and some high end loss, some tapes still sound pretty good, and make me want to get a Rega TT again... :-)

The BX-125 is basically a two head version of the BX-300, made from around 85-88 or so, and is all CPU controlled, so no mechanical playback controls.

I have a service manual for the BX-300, but it refers to a lot of special equipment for testing. Maybe I'll just inspect all the caps carefully and hope for the best.

Thanks

[auplater]

Are you sure the tape is tracking the gap? cassettes are less forgiving than open reel, my old nak 480 bit the dust because of head wear and failure of all the nylon gears controlling the tape motion. Does the head show any wear grooves? The squealing you hear may be "stiction" a well documented problem when head wear and old tapes cause friction and binding. This sounds like mistracking, not azimuth, as in the recorded and playback tracks aren't lining up. Look for idler roller problems/poor contact/hard rubber, to make sure it's not a mechanical problem.

hope this helps.

John L.

[Cobra2]

BX-125 is a fairly simple 2-head machine.
( I have had a couple BX-125, a BX150, a RX-202, a LX-3, and now a "Casettedeck 1")

Azimuth adjustment is on a (springloaded) screw, if I remember correct, it should be the one on the right side of head.

I have found that the simplest method for adjusting, is to mono-couple the players output. I usually make a simple push-button next to the output RCA, and solder a wire to R & L (center) internally, so when I find/borrow a tape out of adjustment, it is a quick job finding the right adjustment.
Just play the tape, press the button, and listen to treble, adjust to highest/cleanest treble.

Arne K

[zeonrider]

TDWesty,
How you know that azimuth is bad (bad adj ).
First : check output level (pb level ), for this job use test tape 400 or 1000Hz. If you have friend with some beter
cass deck , record test (CrO2 tape or Metal ) to 0db .
Put this cassete into your deck & observe both Ch.
If is diferent adj Pb level by trim pots inside of deck .
Good lack.
Rgards zeoN_Rider

[zeonrider]

I , had 480, LX5, and now I have DRAGON (first owner).
I have full service manuals for those decks, never have problems with repairs.
Regards zeoN_Rider

[Cobra2]

Adjustments; Always check the mechanical first! (Head-azimuth)

The level-adjustments should only be done with a proper test-tape.

Arne K

[valveitude]

The BX-125 is basically a two head version of the BX-300, made from around 85-88 or so, and is all CPU controlled, so no mechanical playback controls.

That does not mean it has electronic rec/playback switching in the audio circuit.. In fact, if memory serves me, the Dragon I serviced once had a mechanical rec/playback switch for the audio path...they sound better than the IC switching.

Pop the cover and look.

-Casey