Grundig TK245 overhaul

[Panrock]

Several months ago, I started a thread about an ancient collection of tapes (50+ years old) I had discovered in the loft when it was being cleared out for insulation purposes. I was told that they might still be playable.

Well it looks like I shall soon find out! Today, while helping a friend with a house clearance (masked, at >2 metres!) I acquired what looks like a very nice machine for a nominal sum. It's a Grundig TK245 in very good exterior condition.

I have to say I am thrilled with this acquisition. But what's the opinion on this machine? How old is it? Does it use valves? What is likely to need doing? I have no intention of just turning it on. What might I need to do first.

Thank you for your patience. I am a complete newbie at tape recorders.

Steve

[Panrock]

I've now answered some of my own questions by downloading service information from this site, and a user manual from another site.

This is a hybrid (valve + transistor) machine from around 1969. It looks good quality. I'm looking forward to taking a closer look...

Steve

[DMcMahon]

Hello Steve,

I know well many Grundig models but not this one, it looks a nice machine, 4 track, 2 speed, stereo record.

Mainly valves with 2 transistors, production range was mid to last 60's.

You may be lucky and switch on and it may run OK. It is of a vintage where it should not suffer with paper capacitor related problems, maybe also generally OK with Electrolytic capacitors which occasionally can give problems.

I personally would open it up for a good visual inspection first to make sure nothing obviously untoward. Check the drive belts to make sure not broken/stretched/ gone to sticky goo (unlikely in a Grundig). Also check condition of any rubber coated/tyred idler wheels.

Probably will be quite dirty inside so give a general clean up. Clean the heads and the tape guides and the whole of the tape path using cotton buds with IPA/meths etc. If that is a 2 core mains cable in the photo, I would recommend that it be replaced by a 3 core so it has a permanent earth connection (only do this yourself if you are competent with electrics).

Make sure the mains voltage selection switch is correctly set to 240 volts for UK use, probably set to 220 if it came from Germany.

For the electrics/electronics look for any signs of anything looking/smelling overheated/burnt/stressed. Look out for any Electrolytic capacitors that have bloated bodies and/or show signs of electrolyte leakage.

Look out for any signs of solidified grease on mechanical mechanisms which sometimes can cause problems.

This model is one of a few where it can record in stereo but only play back in mono using the internal power amp and speaker (s). For full stereo playback you either have to connect the second channel to an external amp while using the internal amp for the first channel or feed both channels out to a stereo amp.

[Panrock]

Some very good tips there - thanks. I'll post what I find when I delve in, soon.

Steve

[Ted Kendall]

It's valves and metal rectifiers, single motor with belts, around 1967-8. A decent performer in good condition, with a pressure sling which will aid tape-to-head contact.

[DMcMahon]

Note that if it is the non "u" suffixed TK 245, it possibly may not have the 240 volts selectable option.

[Reelman]

Grundig, for a number of years had in their range a machine that could record in stereo but only playback in mono without an additional amplifier. Such as TK27, TK245 and TK246. It was only at the end of the R2R era that Grundig produced true “decks” such as the TK945 and TS1000 without any output amps and ‘speakers. Although they did produce a number of “TM” chassis recorders without output amps based on existing models for incorporating within Grundig radiograms.
Far earlier the Japanese produced portable self-contained “recorders” and “decks” more suited to be used as a hi-fi separate in a domestic situation. Such as the ever popular Akai 4000D and Sony TC377.
The TK245 was the second model down in the range at the time, only surpassed by the similar looking (but all transistor) TK247 which did have output amps and 4 loudspeakers. They are nice, substantial (read heavy!) machines and the few I have seen in the flesh have all been working even after 50 years. A new set of drive belts would not go amiss and a good service as David suggests.

Welcome to the world of reel to reel, there’s no turning back once the bug bites!

Peter

[Panrock]

Again thanks for your help.

On first look, this machine is set for 240v mains, so OK there. Do you think I'm OK using Halfords cellulose thinners (on a cotton bud) for cleaning the heads? One of its constituents is isopropyl alcohol...

Steve

[ben]

If it is anything like the TK248, the rubber idler tyres tend to harden, giving very poor fast wind. I improvised some new ones from leftover VHS idler tyres.

Personally I'd just power it up briefly, a minute or two at a time, then switch off repeatedly for 10 mins or so, hopefully the mains filter cap will respond okay. Keep your eyes and nose (!) open and be ready to yank the plug if there are any signs of distress.

[paulsherwin]

Use meths to clean the heads if you have some. Witches' brew solvents will probably be OK, but you never know what's in them. You can also use a drop of gin or vodka on a cotton bud if you don't have any meths.

[Panrock]

Thank you Ben and Paul.

Funnily enough I had come to the same conclusion Ben, and have just powered it up, slowly through the bench Variac to start. No sound yet (and no ominous hum) but the machine does 'play' in the spooling sense, though take-up is non-existent and forward fast spooling is weak. Fast spooling back seems OK.

To investigate, the machine will now have to come apart.

Steve

[Panrock]

The top panel has come off and here's the view. I get the impression from how it looks, and from the difficulty in easing off some of the knobs, that it hasn't been off before.

The belts look shot, and will all have to be replaced. Does anyone kindly have a recommendation for a source for 52 year-old Grundig belts?

A full overhaul is indicated otherwise, including lubrication and testing the valves and magic eye. The full story will be told here.

Incidentally, I feel rather bad about the title of this thread. If the mods feel it would be more helpful to rename it to something more informative, like "Grundig TK245 overhaul", I won't have any objections.

Steve

[AC/HL]

... No sooner said.

[Panrock]

Thanks!

S

[ben]

You know, by the look of 'em those flat section belts may be the fibre type that are put under tension only in use. They might be serviceable. Maybe another member could confirm.

You can give that rubber idler wheel a going over with fine sandpaper to improve fast wind.

[Techman]

I very much doubt there will be any need to test valves on this machine. Just give it full mains for a short test with an old tape with something already recorded on it and see what happens.

[DMcMahon]

Agree that you would be unlucky if the valves were unserviceable.

No experience of the flat fabric belts, I think there are 2, the counter one being a normal round belt.

If new drive belts are required then sites such as eBay one can normally find drive belt sets.

[Panrock]

We'll look further into the interesting nature of the 'belts' in due course. Maybe they're meant to be floppy like this!

I have now removed the bottom, and am rewarded with this view - very clean.

The other photo shows the same thing rotated by 90 degrees and with the circuit board cover off.

So far I've lubricated the capstan motor, top and bottom, and cleaned the heads. I shall be replacing the mains lead with a 3-core type and modern 13A (3A fused) plug.

Steve

[DMcMahon]

It certainly looks good condition.

[Reelman]

If the belts are fabric one side and rubber the other then they are similar to the ones used on Telefunken recorders made more than 10 years previously, eg KL65. I have a feeling that they were quite loose but it was 40+ years ago that I worked on one! Looking at a picture on the Radiomuseum’s site confirms it but also shows a spring loaded jockey? wheel to maintain tension.
Daft Isn’t it, I can still remember whilst working on it listening to Alan Freeman’s Saturday afternoon show with Colin Blunstone as the live artist. But I digress.....sorry.

Peter