Fleetwood model 4068... Advice?

[Reece]

As electroking noted, both the coils shown as L2 are on that assembly, and the two lower ("cold") ends of the coils are connected together and to system ground. If substituting a different coil, determine the common terminal and connect the same as before. If the set won't oscillate (as determined by the set tuning broadly, maybe one station all over the dial), reverse the connections of one of the coils.

Main tuning cap alignment: tune in a station of known frequency near 1400 Khz. The trimmer on the smaller section of the tuning cap will move the station up or down the dial until it reads correctly on the dial scale. Then tune to a weak station around 1400 and peak reception with the trimmer on the larger section of the tuning cap.

[electroking]

Hello again,

The reason I suggested trying out the amplifier was to help you find something
stimulating to pursue the project: the amplifier will work even if the radio section
is not fixed. As long as the function switch is set to phono or stereo, the radio
section is not powered (except for the tube heaters). If you have to set this
project aside for sometime, I would suggest that you do some reading on the
principles of superheterodyne receivers (that just means a receiver with a
local oscillator and demodulation at a fixed carrier frequency called the Intermediate
Frequency). Examples of useful books include any old edition of the ARRL handbook,
good old textbooks such as the one by Terman (Electronic and Radio Engineering),
etc. Bye for now.

P.S.: testing with the turntable and an old 78 is fine too!

[VintagePC]

Well... game over for now The TC8S is indeed quite dead... there was crystal dust everywhere.

Looks like I'm on the hunt for a new cartridge. Any recommendations for a drop-in ceramic replacement (TC12H?) or how much I can expect to spend? (and possibly a good supplier in NL?)

Thanks!

[Reece]

Canadian Astatic. Send them your set model number, and all the numbers on your cartridge. They will have one that will work.

http://www.canadianastatic.com/

[VintagePC]

I've sent them an email and am waiting for a reply.

While googling, I came across this:

http://www.angelfire.com/electronic2...ge-rebuild.htm

Anyone tried it before? Or will that hack only work well in a mono cartridge?
I have several piezo buzzers I've salvaged... and it's not as though they are expensive. Perhaps I'll give it a shot.

[electroking]

Originally Posted by VintagePC

I've sent them an email and am waiting for a reply.

While googling, I came across this:

http://www.angelfire.com/electronic2...ge-rebuild.htm

Anyone tried it before? Or will that hack only work well in a mono cartridge?
I have several piezo buzzers I've salvaged... and it's not as though they are expensive. Perhaps I'll give it a shot.

I would say don't bother with that, a good replacement cartridge should not
be that hard to find, and it will come with brand new styli. By the way
I looked at your site (thanks for the credit to me regarding the schematic!)
and I wonder why you concluded that the oscillator coil was shot.
Maybe it's obvious to you, but did you trace the connections to the
rest of the circuit to confirm that something was wrong? Good luck.

[VintagePC]

Originally Posted by electroking

I would say don't bother with that, a good replacement cartridge should not
be that hard to find, and it will come with brand new styli. By the way
I looked at your site (thanks for the credit to me regarding the schematic!)
and I wonder why you concluded that the oscillator coil was shot.
Maybe it's obvious to you, but did you trace the connections to the
rest of the circuit to confirm that something was wrong? Good luck.

You're welcome- when the writeup is finished, anyone here who's contributed significantly will be credited

I figured as much... I'll have a look around to see what I can find locally in addition to AES; chances are a specialty electronics shop may have something.

Re Coil: There are several broken wires coming off the side (click the picture for a larger version, easier to see) and there is no continuity if I test the lower coil with a DMM.

I'm going to give Reece's suggestion a try as soon as I can get back to the project- I think it may be fixable with some care... it looks worse than it is.

[VintagePC]

Okay... Just in time
I dropped by a specialty electronics store and I managed to get his last ceramic pick-up for a good price.

I never heard back from Canadian Astatic, and the cost was less than they asked anyway.

So now I have a Philips GP-815, and I just have to figure out a way to mount it (which shouldn't be difficult- it comes with a small metal plate to clamp it securely; If I drill and tap the plate then I should be able to use the original mounting screw in the BSR tone arm.

Does anyone have detailed specs? All I can find is this page, which offers little help (except confirming that it is ceramic):
http://www.topkaufmunich.de/plaintex...temphilips.php

I would assume the standard tracking weight of around 6g would apply.

(Though I've heard it's better to be on the higher end of the range- which would be ~8g. I know too light will damage the record as the stylus skates around, but what sort of problems would you get with too much tracking weight?)

[VintagePC]

Okay, I'm back at it .

Just for kicks, I asked the guy if he also had any dial cord or tubes... Negative on both counts, but I did win that bet

Anyway, I was able to mount the new cartridge, wire it up and set the tracking weight using a jury-rigged balance and a loonie (which is exactly 6g!).

However, doing a dry run, (nothing connected to the turntable), I can actually hear the sound on the record. It's not loud, and somewhat tinny (kind of like someone standing next to you with their earbuds cranked.)

The needle isn't skating, it is well seated in the groove.

I don't want to damage anything, so I stopped right away... More newbie questions:

- Is that normal, or too much/little tracking force?

-If not, could it be the stylus angle (and should it be 90 bang on, or more/less)?

Finally, I still have the TC8G and TC8S styli... Both look in good shape. Anyone want to buy them to fund my restoration? "Super macro" pics on request.

[electroking]

Many ceramic cartridges produce an audible acoustic signal if you bring your
ear close enough, no need to worry. Good to hear of you again!

[VintagePC]

Well, in that case, the turntable now works!

Back to the chassis... The oscillator got lunched all right. It's well beyond repair.... Off to source a replacement

[VintagePC]

Would it be an idea to re-build the coil? I've calculated the length of damaged wire to be 5m, and I have the same fine stuff on hand.

Could it work, or would the new specs be different enough to require adjusting the set anyway? (what I'm hoping to avoid)

[electroking]

Originally Posted by VintagePC

Would it be an idea to re-build the coil? I've calculated the length of damaged wire to be 5m, and I have the same fine stuff on hand.

Could it work, or would the new specs be different enough to require adjusting the set anyway? (what I'm hoping to avoid)

It will require alignment of the trimmer on the oscillator section of
the variable capacitor, but that's no big deal. IF
alignment (the slugs in the IF transformers) should not be affected.
Rebuilding the coil on its original cardboard core will probably
yield better results than trying to fit a 'universal' replacement coil.
By the way, the exact number of turns matters more than the length
of wire, so try to stay as close to original specs as you can. Also the
wire must be enameled (thin coat of varnish rather than bare wire
or wire with plastic insulation). This is often sold as 'magnet wire'.
Good luck!

[VintagePC]

Unfortunately the coil was so chewed up I couldn't reliably count the number of turns.

However, I did piece all the lengths together and I would assume that with the same total length of wire, wound in the same manner (or as close as possible) would result in the same number of turns.

I have numerous low voltage transformers that I'm never going to use for anything else- I'd thought to salvage the wire from one of those, provided it's not potted. I also have a huge copper coil (magnet wire) from a TV yoke, but I think that's too thick to use. Fortunately, the secondary coil was untouched, and so I have it for both a reference in wire size and winding pattern.

[electroking]

Looks like you did your best to gather all the available info. It's time to start
experimenting! As long as you get the correct phasing (relative polarity of
the two coils), it should oscillate. Personal message to follow within one day,
bye for now.