Sony TC-127 Stereo cassette Deck Checkout

[DMcMahon]

Early 1970's 2 head fairly basic deck, which looks fairly attractive in its imitation wood case. It was sold as fully working with one small fault that the tape does not eject properly.

For its age it is in cosmetically quiet reasonable condition, the piano keys operation feels very solid and positive.

Checking the cassette ejection, the cassette itself does eject but the cassette lid only pops up a little, it looks like there are some pieces missing that the molded plastic hinge parts on the lid should fit onto and a spring for the lid also looks to be missing, will look inside in case the bits are inside somewhere.

There is a Tape Sentinel indicator that I am not familiar which during Play it flickers about once a second and at a faster rate during fast winding.

Playback works well but noticed that when Paused that both VU meters flicker around the low end of their scales, particularly the right channel, this flickering also is present just powered up doing nothing. In paused Play when the volume is turned up quite high on the external amplifier there are strange muffled/echo type sounds present on the right channel and intermittently some strange clicks also on the right channel, the clicks can be seen on the VU meter as a pulsed kick. With normal music levels I don't think the sounds will be noticeable.

Will clean the PB/Record switch to see if that make any difference to the noise, I am thinking it will not. The noise reminds me quite a lot of transistor noise I have experienced on quite a few Akai machines.

[DMcMahon]

Recording test from line in phono's gave good results on both channels, no obvious sign of noise /VU meter flutter when in Record mode.

David

[patrickgnl]

I can’t help with the electronics, but I do know that virtually all Sony cassette decks of this era had similar eject systems.

Upon pressing the eject button the lid would flip open (say five inches) as if spring loaded and held by a catch that you’d just released. A separate lever connected to the eject button would push the cassette up a centimetre or so. I have a TC131SD and TC138sD which work like this.

The TC127 is very similar to the TC134SD which had DolbyB and superceded it.

You may find service manuals for either machine that may help on HiFi Engine…

Patrick

[patrickgnl]

There *is* a copy of the service manual on Hifi engine - here is an illustration that may help you..

[Restoration73]

TC-133CS (built in amps + box speakers) also has an optical movement indicator.

[DMcMahon]

Thank you Patrick, I previously downloaded the service manual.

After getting inside I could see that the two cassette lid holders and 1 spring were inside in correct locations. It was impossible to fit the cassette lid to the lid holders, looking at the drawing I could see that the curved over ends (that hook onto the shafts of the lid holders) of the plastic hinges, are both broken off/missing.

Later maybe able to make some hooks (curtain hooks come to mind) and try and glue onto the broken ends of the hinges. When I removed the bottom cover a small shaped metal plate fell out, looking at the drawings I think it is the erase head top cover. Several other miscellaneous pieces fell out when I removed the top cover, think just a case of identifying where they belong and glue them back in.

Been trying to see the PB/Record switch to be able clean, it but cannot even see it, looks like I will have to remove the main board to see/access.

David

[patrickgnl]

Well i suppose at least the manual gives you some idea as to what the cassette hinges should look like. If a remember correctly you remove the lid by gently pushing the lid backwards so can see why the plastic would snap if not done carefully.

I see what you mean about the rec/pb switch but at least access (via removal of the circuit board) is covered in the service manual.

It looks like a good find to me and in pretty good cosmetic condition. I hope you get it working.

I am a big fan of Sony TVs and HiFi from that period….

Patrick

[DMcMahon]

Originally Posted by Restoration73

TC-133CS (built in amps + box speakers) also has an optical movement indicator.

I have a TC-133 (not yet looked at), in the User Instructions manual it refers to a Tape Pilot green bar that moves to the right on Play, I assume this is equivalent to the Tape Sentinel indicator on the TC-127.

David

[unitelex]

Regarding the VU meter flicker and the noises, as you mentioned the first port of call would be the record/play changeover switch/wafer - strip and clean.
If not that then it seems to be confined to the pre-amp used in play mode. So transistors as you say or caps.
Had quite a few tape machines in recently with raised noise floor typically hiss, needed new transistors in the pre-amp, and some needed bias resistors changing to metal film.
Oh and the Nakamichi needed some film caps replacing.

[DMcMahon]

Cleaned the left and right PB/Record slide switches. Resoldered quite a few dodgy looking soldered joints on the main board.

Noticed that the CR snubber across the mains on/off switch (CP101 0.033uF + 120Ohm 600V) was rather bloated on both sides, so replaced it with a 0.1uF 275VAC X2 Polypropylene suppressor).

Cleaned the heads and some other general cleaning, glued the erase head top metal cover back on.

During dis-assembly had to remove the mains voltage selector switch to get the top cover off and subsequently the paper ident showing the various voltage taps fell off, so had to double check for correct positioning/orientation of the label before gluing it back on.

For reference the mains transformer primary winding resistances for the various voltage selections were:-

100V = 78 Ohms
110V = 86 Ohms
117V = 91 Ohms
125V = 99 Ohms
220V = 195 Ohms
240V = 214 Ohms

Recording and Playback working well, now no VU meter fluctuations or noise.

Wondered how the Tape Sentinel worked, thought it was some fancy monitor/control linked into tape speed servo. Saw on schematic that the Tape Sentinel lamp was across the same secondary winding that powers the power on indicator, so thought how could the Tape Sentinel lamp flash on/off when the power lamp stays lit all the time.

Now see that it is a simple mechanical indicator, there is a metal flag with 2 vanes that is driven by a drive belt and the vanes rotate above the Tape Sentinel lamp and when the vanes are directly above the lamp this stops the light from the lamp going up a tube, at the top of which is the Tape Sentinel indicator on the deck.

David

[Whaam68]

The “tape sentinel” type running indicators seem to be a thing on some top loading decks of this era….I’ve got a Teac A-450 and an Akai gxc-310D and both have a bulb in a belt driven slotted metal drum that rotates giving what externally looks like a “high tech” pulsing running light. One of my favourite features. In my limited experience decks of this era sound surprisingly good with a warm mid range perhaps because of the ferrite heads. They are also well built and easy to access to work on.

[ben]

I had a Sharp deck of this era with the same flashing tape run indicator.

Nice Sony you got there!

[DMcMahon]

Originally Posted by DMcMahon

Early 1970's 2 head fairly basic deck, which looks fairly attractive in its imitation wood case.

I can see now that the cabinet side board is actually veneered wood.

David

[ButchJames]

This TC-127SD looks very similar to the TC-134SD I have and repaired.
Solid deck, that has taken me 30-40 hours to get up to the default standard of the machine.

Also, I've just noticed that there is no dolby for this machine?, so it must pre-date the 1972-onward TC-134SD?

[DMcMahon]

Hello and welcome to the Forum.

Yes no Dolby and no manual or auto tape type selection, so a basic deck really but looks nice and performs well.

David

[ButchJames]

Originally Posted by DMcMahon

Hello and welcome to the Forum.

Yes no Dolby and no manual or auto tape type selection, so a basic deck really but looks nice and performs well.

David

Thank you.

Yes, like many, I am often drawn to the visual appearance of a deck. It looks better than my TC-134SD IMO.

I did write an extensive blog about the 134SD, but have withdrawn it as I've modified things again. Just purchased
another for 'parts'.