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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 15th Feb 2020, 11:16 am   #1
DMcMahon
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Default Saba TK75. Any Thoughts?

Does anybody have any experience of the Saba TK75 or similar Saba TKs ? I quite like the look of the one attached.
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Old 15th Feb 2020, 10:30 pm   #2
reelguy
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Default Re: Saba TK75 Any Thoughts

I have a SABA TK230 stereo recorder. Weighs a ton. First one I have ever come across in all the years of collecting reel recorders. Sounded good when I tried it last but on the back burner at present. Not easy to get info on these M/cs. not seen a TK 75 though.
Peter Reelguy.
PS, I'm not far from Worthing.
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Old 16th Feb 2020, 10:21 am   #3
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Default Re: Saba TK75 Any Thoughts

Hello Peter, thank you for your Saba comments, yes I had seen that you are not that far away.

I am considering purchasing the TK 75 in the photo, it looks in really good condition. Seller says it is fully working mechanically but there is no sound output. I am awaiting a close up photo of the heads to see if I can determine if they are badly worn (especially after my ongoing experience with the Grundig TK 819 heads).

If the heads are OK (and not open circuit) then a reasonable chance of fixing no sound and I like a challenge.

The asking price is not too bad, however it has a particularly large shipping cost.
David

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Old 16th Feb 2020, 4:32 pm   #4
dazzlevision
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Default Re: Saba TK75 Any Thoughts

Quote:
Originally Posted by DMcMahon View Post
The asking price is not too bad, however it has a particularly large shipping cost.
David
They weigh an absolute ton!

I had one briefly a couple of years ago.
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Old 16th Feb 2020, 11:48 pm   #5
ben
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Default Re: Saba TK75 Any Thoughts

Quote:
Originally Posted by reelguy View Post
I have a SABA TK230 stereo recorder. .
I also have one gathering dust. It needs a new belt for the capstan drive, which is a rather thick flat type. Without a replacement it struggles to get to 7 1/2 ips.
I also had to do something to (I think - been ten years or so now!) the mains smoothing can as the terminals were unprotected and it was almost shorting to metal work! Lovely controls on it though. Semi electromechanical. Must get it going one day.

With regard to the Op's model, which looks almost ten years earlier. Do check heads and see if you can find a schematic. If the 230 is anything to go by, I would imagine there is an abundance of rubber idlers etc, which may be hard and noisy by now.
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Old 16th Feb 2020, 11:51 pm   #6
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Default Re: Saba TK75 Any Thoughts

Now brought it and have a service manual with schematic also ordered.
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Old 18th Feb 2020, 9:49 pm   #7
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Default Re: Saba TK75 Any Thoughts

Unusual shape from the underside.
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Old 11th Mar 2020, 5:13 pm   #8
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Default Re: Saba TK75 Any Thoughts

Several days ago unpacked the Saba that a had arrived a couple of days before.

Unfortunately it has obviously had a bad knock during shipping. The lid was off and the Take Up Reel Table top hub was lying in the box. The right hand metal spigot in the lid (spool retainer I assume) is badly bent and partially has pushed up through the lid.

Fitting the lid on, it is seriously misaligned with the unit. The right hand side of the chassis has a noticeable gap to the case surround metalwork, where I think the metalwork has been pushed downwards.

Also a few other minor knocks.

So more work than I anticipated, most of it metal straightening, hopefully the Take Up Reel Table will be OK after the top hub is refitted.
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Old 13th May 2020, 10:52 pm   #9
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Default Re: Saba TK75 Any Thoughts

Just about to get back to this and have a look inside, apart from the mechanical shipping damage, it was supposed to be mechanically working but with low sound volume.
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Old 14th May 2020, 12:15 am   #10
garry71
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Default Re: Saba TK75 Any Thoughts

It's a shame about that damage, it looks like a nice machine. Hope you get it going ok.
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Old 14th May 2020, 10:14 am   #11
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Default Re: Saba TK75 Any Thoughts

It is a left 50s 2 track mono (2 internal speakers), 2 speed, auto reverse on play and record.

Took the top cover off the Take Up Reel Table and saw that an e-clip has come off the mounting shaft, so looks like it will all fit back OK and hopefully has not been affected by being knocked off during shipping, very heavy with its lead weights.

Removed top panel, looks vgc inside for its > 60 years.

Tape counter drive belt is broken and a very small belt on the counter itself looks well stretched. The tape counter has 2 thumb wheels, the one of the left is sprung loaded and can be moved, no idea yet what this does.

Struggling at the moment to remove the chassis from its box, there is a 7 way connector (a bit like a valve base) that has to be unplugged so that the chassis can be lifted out leaving the output stage. I have unplugged it, but the plug appears to be too large to go through a gap in the chassis (but obviously it must somehow go through), the chassis is really heavy which makes it really difficult trying to lift it out and not damage the connector/connected cable.

There are 2 large rotary control knobs on the front of the unit, these are difficult (stiff) to rotate and additionally look to be too far recessed in, I assume they must be part of the Output stage unit, once I get the main chassis out will be able to see them properly.
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Old 14th May 2020, 2:53 pm   #12
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Default Re: Saba TK75 Any Thoughts

After a big struggle got it out of it case. Had to make up some lifting straps to put around the frame but it kept fouling and would not come out, I tried it upside on pillows but no good.

Got the 7 way connector to go though chassis gap by removing 2 securing screws for the selector switch mounting and with brute force levering the switch bracket over a little to allow the connector to pass, what a rubbish design !

It was fouling on several areas:-
1. The mains cable (cut it off as will replace with 3 core anyway).
2. The 2 large round control knobs that are part of the Output stage, found that the 2 securing screws for the output stage were somewhat loose so that unit was leaning backwards in the way of the chassis and also explained why the knobs were recessed too far back into the case.
3. A knurled screw head for the cover over the mains voltage selection switch/fuses.

Interesting piece of silver paper over one of the fuses !

Three old Wilma paper capacitors in the Output stage amp, will replace, but first will test the amp voltage wise.

The chassis looks like a nightmare to work on access wise, hopefully will not have to do much.
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Old 14th May 2020, 7:37 pm   #13
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Default Re: Saba TK75 Any Thoughts

I never realized this was a reversing machine. Seems to be a similar concept to the Grundig TK819 et al, with its centrally placed capstan and mirror-image tape path on either side.

That foil I suppose is a replacement for a blown fuse. At least it's not an M5 bolt!
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Old 14th May 2020, 8:18 pm   #14
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Default Re: Saba TK75 Any Thoughts

The fuse was not blown but was loose in its fuse holder, so maybe someone used the foil to make the fuse fit better ! I removed the foil and carefully bent fuse holder contacts (only has top contacts) down to get a good fit (contacts are still springy).

I replaced this 800mA fuse with 500mA, the rating shown for it on the plate.
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Old 15th May 2020, 10:02 am   #15
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Default Re: Saba TK75 Any Thoughts

Converted the mains cable from 2 core to 3 core, really difficult as could not see where the cable went to inside the machine and had to inline soldered joints to convert the cable and it was extremely tight getting to the cable (which I had to cut off during chassis removal) behind the mains voltage panel.

Powered up OK, tape transport works well with tape, not yet tried automatic reversing, the tape transport keys illuminate when selected. Found the second thumbwheel by the left side of the tape counter is not a counter thumbwheel, but the tape speed control knob.

Mains On/Off switch does not work (is permanently on).

In early stage of checking out the DC HT supplies. Main HT measures 283 volts, but this is mostly off load, because I discovered that the HT supply first goes into the Output Stage module, then is returned back out to power the other 4 valves. At the moment I have the Output Stage (output amplifier) module disconnected.

There appears to be a 70 volt drop across the HT 200mA fuse as only get around 211 volts at the output of the fuse ?? More checks to be done later in the day.
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Old 16th May 2020, 9:20 am   #16
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Default Re: Saba TK75. Any Thoughts?

Found the > 70 volts drop across the 200mA HT fuse was due to very bad contact resistance on the copper (looks like copper) fuse holder contacts. There was Verdigris on the underside of the copper contacts and despite cleaning with crocus paper and contact cleaner I had a hell of a job obtaining consistent good contact resistance/volt drop free.

The other 2 fuse holders are not as bad but also suffer from poor contact resistance, but the AC voltage on these seems to cope better than the DC voltage on the 200mA fuse.

Ideally I would like to renew these poor fuse holders but due to their single side contacts, normal double sided fuse holders would be too deep/high for the available space plus would not really want to disturb the fuse/mains voltage selection panel again with the very tight connections behind including the very fine/delicate transformer wires.

So will press on with existing fuse holders to see how it goes. Currently have got good contact resistance/virtually zero volt drop across the 200mA fuse, but am not confident how long this will last.

Maybe the poor contact resistance is why the 500mA AC mains fuse had the silver foil around it.

Powered up again this time with the Output Module connected, first removing the ECL 82 Triode Pentode valve. Have not seen an ECL 82 for a long time and had almost forgotten about Triode Pentodes until the other day when I read Garry's comment in the "Disconnected Speaker" thread.

After powering up found there was zero DC voltage coming back from the Output Module to the chassis. Traced problem to a broken yellow wire at pin 2 of the 7 way connector, this connects the DC supply from the output side of the 360 ohm smoothing choke L3 in the Output Module to pin 2 for the DC HT supply for most of the electronics in the chassis (designated 260V B).

So will repair the broken wire and test again. There are 4 old Wima waxed paper capacitors in the Output Module that I will replace, but will first out of interest, will test for leakage/DC voltage passing with power on them.
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Old 17th May 2020, 11:54 am   #17
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Default Re: Saba TK75. Any Thoughts?

Repaired the broken yellow wire on pin 2, not to be confused with the yellow wire on pin 1 which is the inner/live core of a screened cable.

This restored DC power to the main chassis and for the first time I saw the EM84 Magic Eye valve light up when Record selected, not a very good/bright display though.

Tested the 4 old Wima waxed paper capacitors in the Output module, all leaking (electrically)/passing DC voltage, particularly bad was the Triode Anode to Pentode grid coupling capacitor C43, so replaced all 4. All the various DC voltages at the output valve are now good and output is live. With volume turned up, can easily induce hum into the speakers by probing the valves pins with test meter or scope and by waving my hand close to the components can induce hum also and when pushbutton controls are operated get loud clicks from the speakers. So I think the output amp itself is basically OK now.

Tried playing a tape (several to be sure) but no playback sound at all and no audio signal is reaching the input of the output amplifier.

So now in early stage of looking at the pre-amp stage around the EF 86 and ECC 81 valves. This is difficult to work on (especially compared to the output amp) as loads of components all crammed in.

There is quite a bit of very poor soldering at some of the components. While gently moving components to identify them and identify the valve pins, one capacitor fell out completely and another 4 capacitors one end came away disconnected, all due to very dry soldered joints. There may well be other poor connections.

So need to resolder the components and in some cases work out where they should actually connect to. Once that is tidied up, then will have a look at the DC voltages at the 2 valves.
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Old 17th May 2020, 11:37 pm   #18
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Default Re: Saba TK75. Any Thoughts?

After tidying up the atrocious soldering and replacing the EF 86 anode to ECC 81 grid coupling capacitor (very leaky) 0.5uF C19, now have good playback in forward play but nothing in reverse play.

Next need to do recording in both directions then see what playback is like.

Have been using the schematic in the SAMS Photofact Folder Service manual which is very good. Tonight downloaded the German schematic from Radiomuseum.org and see that the component number designations are totally different, that is a little confusing.
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Old 18th May 2020, 7:30 pm   #19
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Default Re: Saba TK75. Any Thoughts?

From some very quick microphone and line recording tests, recording and playback work in both directions, the tape I played yesterday must not have had any recordings on track 2 (another reminder that I need to make some reference tapes !).

There are some issues to investigate/fix though.

1. On line recordings the playback is distorted most likely due to my Hi-Fi phono signal being too strong, I need to fit a resistor attenuator to the cable and try again.

2. The recording level control does not work, it is like the recording level is automatic. The description of the TK 75 says to push the control switch down to put it into automatic mode, where it then will automatically change direction at the end of tape, it does not say if the recording level is also set to automatic by the switch. I get the same results with the switch up or down.

I need to check the electronics to try and see what is happening.

3. Erase is not working in Forward recording so you end up with the original recording (s) as well as the new recording, hopefully this is not the forward erase head itself, need to check it all out. Erase works in reverse recording.
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Old 19th May 2020, 4:13 pm   #20
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Default Re: Saba TK75. Any Thoughts?

Not much more done on the TK 75 yet, as had a higher priority to do some gardening, my wife's, not my priority

Just been having a quick look at why the Input/recording level control does not work manually during recording and got side tracked a little. I removed a metal cover and next to the long shaft of the Input/recording level is a set of contacts that are not being actuated by anything. Pretty sure they are the contacts that are actuated when the Input/recording level control is pushed down for automatic operation.

Looks like there must be a piece missing either from the metal piece fitted to the shaft or the actual contacts, there is a little metal plunger on the contacts that has to be pushed to change the contacts over. I think I can see these contacts in the schematic identified as "Part of automatic switch". On the schematic there is another pair of contacts also identified as "Part of automatic switch" but I cannot physically see any other contacts ?

I would love to remove the input level control to be able to see better but it looks extremely difficult to do.

I do not think these contacts have anything to do with the record level not manually working. Later when I find a tape with metal foil leaders I will test the automatic turnaround (may have to manually operate the contact set.
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