Problems with a Pioneer CT-F1250 cassette deck

[Mike Lee]

Hello all,
I recently rescued an old and beautiful Pioneer CT-F1250 cassette
deck from a friend's trash heap! It was in great shape but
appears to need some work to bring it back up to spec again.
Most seriously, there is a large power resistor (7W, 12ohms) on
a vertical board that overheats (to the point of smoking!). I believe
this may be related to the quartz lock circuitry, because it only
happens during playback and record, and the circuit board has
one section that is labelled "pulse count". The second
issue that it seems to have is that the tape calibration doesn't
seem very stable -- the ideal setting for each knob
(bias/level/eq) seems to fluctuate over time, even over the course
of a calibration run.

Can anyone offer any hints and tips in troublehsooting and repairing
one of these grand decks? Or possibly someone willing to share a copy of
the service manual? It is in fantastic shape and I'd hate to
see it go to waste!

Thanks in advance,
Mike

 

[Nigel]

[email protected] (Mike Lee) wrote in

Hello all,
I recently rescued an old and beautiful Pioneer CT-F1250 cassette
deck from a friend's trash heap! It was in great shape but
appears to need some work to bring it back up to spec again.
Most seriously, there is a large power resistor (7W, 12ohms) on
a vertical board that overheats (to the point of smoking!). I believe
this may be related to the quartz lock circuitry, because it only
happens during playback and record, and the circuit board has
one section that is labelled "pulse count". The second
issue that it seems to have is that the tape calibration doesn't
seem very stable -- the ideal setting for each knob
(bias/level/eq) seems to fluctuate over time, even over the course
of a calibration run.

Can anyone offer any hints and tips in troublehsooting and repairing
one of these grand decks? Or possibly someone willing to share a copy of
the service manual? It is in fantastic shape and I'd hate to
see it go to waste!

Thanks in advance,
Mike

Have you checked the motor ? If it's faulty and drawing heaps of current,
you should be able to feel it getting warm.

 

[Mark D. Zacharias]

Except if it's really shorted, the resistor mentioned is toast long before
the motor gets hot. One could just disconnect the motor and see if the
resistor stops heating up.

Mark Z.

 

[b]

I have 2 even older pioneers -a ctf-1000 (3 head, blue flourescent VU
meters) and a ctf 9191 (I think those are the models, dont have them
nearby). In the former, the motor driving the spools was faulty and in
the latter the play solenoid drew too much current and blew a
transistor in its feed. Dont have a service manual unfortunately. Not
familiar with your model. Sounds like a nice bit of kit. Does it have
the blue meters also?
Good luck Ben

 

[Mike Lee]

Thanks both of you for the feedback. I will try disconnecting the
motor and
seeing what happens. Strangely, though, I'm fairly certain that the
resistor
heats up only during playback and record ... and since the capstans
are always turning, and the hubs turn for all transport modes
including FF and RW, it doesn't seem likely that the motor would be at
fault. But I will try it anyway, and post back here with the
results...

 

[Mike Lee]

Yup, it does have the blue meters. According to the silver pioneer
website,
ths was their flagship deck in 79 and 80 ... a 3 head model with tape
calibration facilities. build quality is strikingly rugged ... I've
seen receivers with smaller transformers than the one in this sucker!

Still have my fingers crossed that it will be a relatively simple fix
to get it up and running again. (hopefully just a few common
components...)

Mike

 

[Bob Shuman]

Mike,

I too have a Pioneer CTF-1000. This is the model that was a step down from
the
1250 and had the blue fluorescent VU meters. I purchased it new in 1979 and
used it for many years. As I recall, it had a
problem right out of the box with clicking and popping noises during
playback, but this was due to a missing ground wire that needed to be added
in the field due to a poor design. I had no other problems and it worked
pretty much flawlessly for 10-15 years. Eventually I had trouble with the
drive belt (in play and reverse FF) slipping so stopped using it. About a
year or two back I went in and replaced all the rubber (3 belts IIRC, idler)
and it started working again although the original grease that was used had
stiffened up due to lack of use so it was being a bit finicky.
Unfortunately, it does not get much use anymore since we have gone pretty
much 100% to CD-ROM media.

I agree the unit is worth salvaging ...

Bob

 

[b]

Silver pioneer website? sounds like I need to take a look there!
Could you possibly post the URL?
cheers, Ben

 

[John A. Weeks III]

Silver pioneer website? sounds like I need to take a look there!
Could you possibly post the URL?
cheers, Ben

http://www.silverpioneer.com. They are in the process of moving,
so it might be http://silverpioneer.netfirms.com by the time you
see this posting. I also have my silver collection displayed on
my website, http://www.johnweeks.com/stuff/pioneer.

-john-

 

[b]

You have a fine collection of pioneer stuff there!
However I have to say that your site would be a lot better without
all that right wing jingoistic warmongering crap located in the 9-11
/flag section, especially those sections that link saddam Hussein to
Al Quaeda etc etc. Even more so since that has been proven as Bush
Junta lies. Personally, I would distance myself from such spin.

respectfully yours
Ben

 

[Tom W]

If you're still interested, that resistor is in the pinch roller solenoid
ckt. There should be a transistor wired in parallel to that resistor which
is turned on for a short time when the solenoid activates to give a current
boost to pull the plunger in. When the transistor is off the resistor is in
series with the drive transistor and the solenoid. Could be the boost
transistor is open leaving the "hold" ckt to pull in the solenoid. If the
pinch roller isn't getting enough tension against the capstan that could
explain your other problem. Or it could be a worn head.

tw

 

[MIkemaxcel]

` the tape calibration doesn't
seem very stable`
you can solve it by cleaning the calibration switch.