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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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27th May 2020, 2:53 pm | #41 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Put it all back, with a neoprene sleeve pushed up over the bottom shaft to locate the meter driving pulley instead of the damaged circlip. This seems secure and is more easily removable.
However the take up spool now doesn't turn at all, except when fast forwarding.
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27th May 2020, 3:28 pm | #42 |
Dekatron
Join Date: Apr 2005
Location: North Wales, UK.
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Re: Grundig TK245 overhaul
Oh dear! Well, let's start with the obvious - is the belt on correctly? as you'll see, the FF is idler driven from the main pulley, and this is a belt driven slipping clutch. Not much else to it. However, do check the pulley for the counter belt isn't too tight. There isn't much torque available so the reel needs to be free to spin. Also check the brake isn't on. You'll soon have this spinning again.
That machine really does look in nice condition. As Peter says, reversing the pads should do the trick. As an aside, I think I have a spare degausser in the workshop. If you want to borrow it just ask, though it'll be around £3 to post. |
27th May 2020, 3:37 pm | #43 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Glyn, this is really kind of you. I'll hold fire on taking you up though until I've tried the 'switch-off bias' trick. It's worth noting the playback seems fine, free of the slightest flutter, and with a CD-like velvety background silence. It's everything I had hoped from a Grundig.
I seemed to have pushed the counter drive pulley too firmly down its shaft. Pulling it back slightly made the take-up action come to life. Next to check if it's firmer and more reliable than before...
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27th May 2020, 3:42 pm | #44 | |
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Re: Grundig TK245 overhaul
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27th May 2020, 3:57 pm | #45 |
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Re: Grundig TK245 overhaul
Based upon my own personal R2R experience, I consider that normally one would be unlucky to damage heads/make them go open circuit by testing their continuity, particularly when using digital test meters.
Having said that, last year when working on one of my Uher Royal de Luxe diagnosing a dead left channel, found that the left channel of the head was open circuit. The right channel worked OK and the head measured good continuity but a relatively short time later the right channel died and the head was then found to be open circuit. These were Bogen heads which have a reputation for suddenly dying, so I do not really think that me testing its continuity led to its later failure. Personally I have not experienced (nothing obvious anyway) the sound degradation of a magnetised head after head continuity checks. |
27th May 2020, 4:59 pm | #46 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Well, the take-up still works, sort of, but still isn't firm enough for when a full 7-inch spool is put on, or anything like it.
I've tried cleaning all surfaces that are transmitting drive, and abrading the driven edge of the large disc. I've also tried fiddling with the 'adjusting screw' setting (my name), which changes the position of a small interposed 'jockey wheel'. It's all on the attached picture. I fear the problem is basically general wear.
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27th May 2020, 5:36 pm | #47 |
Nonode
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Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Further info: it seems to be any weight on the take-up platter that's the killer, in 'play' mode. For example, I placed a reel of solder on the platter (otherwise empty) and that stalled it.
I'm sure we'll get to the bottom of this.
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27th May 2020, 7:08 pm | #48 |
Dekatron
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Re: Grundig TK245 overhaul
I think you'll need to ascertain whether the reel is slipping against the lower white surface, or the white pulley is itself slipping as the belt's loose. Easier said than done, though!
I would doubt that a digital meter would pass enough current to magnetise the head, but an AVO 8 probably would. Like others, I have had Bogen heads fail for no obvious reason, and I have a nice Grundig TK141 that has an O/C on one head track. Annoying as it's a good machine otherwise. I like Grundigs of this era, but find the earlier machines unpleasant to work on. |
27th May 2020, 7:32 pm | #49 |
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Re: Grundig TK245 overhaul
So is the Take up spool now free to manually rotate (should spin quite easily) with brake off ?
When the tape up spool struggles in Play does the tape still get fed through by the capstan operation ? |
27th May 2020, 8:24 pm | #50 | ||
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Quote:
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I say 'became', because I have now solved this problem... by inserting a washer between the bottom gubbins and the white disc bearing the furry ring. Was there a washer there originally that flew out when I first disassembled? So I started listening to the tape that has come with this machine. On this, someone was tuning through the FM radio band in the year 1981. I was able to deduce the year from one of the news items. Is there a sort of 'analogue' smoothness to the sound or am I imagining it? Whatever, the quality is really excellent and it makes strangely fascinating listening. I am now a R2R tape 'convert'. More developments soon.
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27th May 2020, 10:05 pm | #51 |
Dekatron
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Re: Grundig TK245 overhaul
That is really good news. Does it have the flat spring arm item 2 in the Service manual that has a flat washer above it, that sits below the white piece ? I assume the ends of item 2 most sit on the 2 pads (item 1).
It may be imagination/wishful thinking but I do think R2R analogue does sound particularly good. |
28th May 2020, 6:59 am | #52 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Unfortunately I don't have the proper service manual, only The Radio & TV Servicing Book article, so am unable to refer to it to answer your question. However I suspect the answer is yes. Thanks for your continued interest.
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28th May 2020, 10:43 am | #53 |
Nonode
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Re: Grundig TK245 overhaul
I've just confirmed the Recording function erases the tape as it should. As for making some actual recordings and testing the auto-recording-level and low level output, I shall now have to make up a fiddly DIN lead.
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28th May 2020, 11:40 am | #54 |
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Re: Grundig TK245 overhaul
Page from the manual showing the reel tables.
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28th May 2020, 12:38 pm | #55 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
Yes, and there's the washer. Thanks. If I find the original, I'll put it back.
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28th May 2020, 9:08 pm | #56 |
Dekatron
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Re: Grundig TK245 overhaul
If you want a Service manual it can be downloaded FOC from sites such as hifiengine.com and audioservicemanuals.com, in German though so some of it can be hard work.
I find automatic translation of German technical manuals sometimes results in some very odd/confusing information in English, some of which with detective work you can work out what it is supposed to say in English. Last edited by DMcMahon; 28th May 2020 at 9:36 pm. |
28th May 2020, 9:32 pm | #57 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
That's good to know. I've already joined Hifi Engine.
Otherwise, I've now successfully recorded tone, and put the Grundig back together. I shall be ordering some suitable DIN leads.
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3rd Jun 2020, 9:45 pm | #58 |
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Re: Grundig TK245 overhaul
Liked the look of yours so much, so I have just brought one, although not as good condition as your one.
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7th Jun 2020, 10:35 am | #59 |
Nonode
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Re: Grundig TK245 overhaul
Good luck with yours, and again thanks for all your help. I'll await news of progress with interest.
I've got started on exploring my box of old tapes now. It's funny hearing myself at school 55 years ago. The Grundig is proving utterly reliable. Steve
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7th Jun 2020, 11:08 am | #60 |
Nonode
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Location: Worcestershire, UK.
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Re: Grundig TK245 overhaul
As I mentioned in a previous thread, these tapes had been appallingly badly stored, and were discovered in the loft after being neglected for decades - exposed to heat and cold and covered with grit. I then cleaned them up - and they still play (!) though the audio quality of some of them is a little muddy. Others are surprisingly good.
On the very worst stretches (at the outside of the tape) I've noticed a weird effect whereby the tracks previously recorded over can still be heard under the newer tracks. It's as if their erasing left something behind that 'rose again' later. Is this a recognised phenomenon? One other question. If it's not allowed to test heads with a meter for continuity, what is the correct way to test them? Steve
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