1st Sep 2022, 4:53 pm | #61 |
Heptode
Join Date: Jan 2011
Location: Croydon, London, UK.
Posts: 773
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Re: Grundig tk 23 L speed issue
It's reasonably easy to check the speed of your tape recorder by using a measured length of tape.
To do it, preferably on a tape that isn't of any importance to you, make a mark on the back of the tape somewhere near the start of the tape. You can use a chinagraph pencil, a wax crayon or a marker pen. Measure along the tape 190.5cm from the mark you have made and make a second mark at that point. Thread the tape onto your tape recorder and line the first mark up with the exit point from the head cover. Play the tape and measure the time until the second mark appears at the exit point from the head cover. If the tape is running at the correct speed, it should take 20 seconds. If it is running fast it will take less time and it will take longer if running slow. The test should allow you to determine if it is the Akai or the Grundig that is running at the wrong speed. Paula |
1st Sep 2022, 5:55 pm | #62 |
Octode
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,493
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Re: Grundig tk 23 L speed issue
Thank you Lawrence. Learn something new every day!
Graham, you're spot on. In trawling through Facebook, I can see the 50/60Hz control is between the spools. Paula, you're a star. Your recommendation should nail the issue. Chris Last edited by simpsons; 1st Sep 2022 at 6:04 pm. Reason: Additional information |
1st Sep 2022, 7:41 pm | #63 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,604
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Re: Grundig tk 23 L speed issue
The TK 23L and all its numerous associated series siblings are not idler drive.
The motor pulley drives a belt that directly drives the flywheel, the capstan being part of the flywheel. There is a single rubber tyred idler wheel that is driven by the motor pulley and then the idler wheel drives the Take Up reel table in Fast Forward wind. David |
1st Sep 2022, 7:59 pm | #64 |
Octode
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Location: Morden, Surrey, UK.
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Re: Grundig tk 23 L speed issue
Most single motor decks require an idler somewhere to obtain the opposing direction wind / rewind.
An exception was the EMI TR50 series where the take up was B wind (oxide out) but then it used idlers to the spools anyway..... |
1st Sep 2022, 8:09 pm | #65 |
Dekatron
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Re: Grundig tk 23 L speed issue
For the Grundigs in question the motor pulley directly drives the Supply reel table in Fast Rewind.
David |
1st Sep 2022, 8:43 pm | #66 | |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
Quote:
Last edited by ubaldojhp; 1st Sep 2022 at 8:48 pm. |
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1st Sep 2022, 8:45 pm | #67 |
Moderator
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Re: Grundig tk 23 L speed issue
Result!!
24*50/60 = 20 . or 20*60/50 = 24 .
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
1st Sep 2022, 8:49 pm | #68 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
The akai as far as I know does not have a 50hz/60hz selector
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1st Sep 2022, 8:51 pm | #69 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
This is the Akai
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1st Sep 2022, 9:17 pm | #70 |
Dekatron
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Location: Worthing, West Sussex, UK.
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Re: Grundig tk 23 L speed issue
I have never seen a 4000DS that does not have the 50Hz/60Hz adjustment, all mine have it.
Post a photo of your rear panel ident label. David |
1st Sep 2022, 9:34 pm | #71 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
Here you have them mate
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1st Sep 2022, 9:43 pm | #72 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
I got it a few years ago in a barter and the previous owner told me that nothing had ever been done to it. Since I didn't have another one and it worked well, I've been leaving it but I've been wanting to do a set-up for a long time. This may be a good time
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1st Sep 2022, 10:21 pm | #73 |
Octode
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,493
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Re: Grundig tk 23 L speed issue
Hi Ubaldo
My Spanish isn't too good but should I be you, finding it was the Akai that was faulty, which at least could record and playback OK, made me think "maldito." Chris |
1st Sep 2022, 10:21 pm | #74 |
Dekatron
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Re: Grundig tk 23 L speed issue
So your 4000DS machine is 50Hz only but appears to be running like a 60Hz machine.
Checking one of my dual frequency 4000DS's I see that the flywheel and also the motor pulley has 2 steps of slightly different diameter. For 50Hz running the drive belt runs on the smaller step of the fly wheel and the larger step of the motor pulley and the complete opposite for 60Hz running. So if (maybe a big if) your machine has the same 2 step flywheel and 2 step motor pulley, then one feasible explanation could be that at some time the drive belt has been replaced/disturbed and manually incorrectly fitted on the 60Hz steps. The photos show the belt position on the flywheel, could not see the motor pulley well enough to take photo but you can feel the different step diameter and the belt should go straight across (not at an angle) from the flywheel to the motor pulley. First photo is 50Hz with the belt on the smaller step of the flywheel and second photo is 60Hz with the belt on the larger step of the flywheel. David |
2nd Sep 2022, 10:12 am | #75 |
Dekatron
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Re: Grundig tk 23 L speed issue
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2nd Sep 2022, 10:14 am | #76 |
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Re: Grundig tk 23 L speed issue
The Spanish mains frequency is 50Hz.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
2nd Sep 2022, 10:26 am | #77 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
I want to thank everyone for your help and apologize for my mistake. I'm going to repair my Akai and I'll tell you
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2nd Sep 2022, 6:02 pm | #78 |
Dekatron
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Re: Grundig tk 23 L speed issue
Just for completeness of information.
The 50/60Hz dual frequency Akai 4000DS in addition to the mechanical 50/60Hz setting also has an electrical 50Hz/60Hz switch setting. When switched to 60Hz the voltage supply to the motor/run capacitors is increased from 100V to 120V and the 0.5uF run capacitor is disconnected from the 2uF run capacitor that it is paralleled to in 50Hz setting (the 2 run capacitors are in a dual can), i.e. 50Hz = 2.5uF, 60Hz = 2uF. David |
14th Jan 2023, 11:44 pm | #79 |
Triode
Join Date: Dec 2017
Location: Cartagena, Spain
Posts: 37
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Re: Grundig tk 23 L speed issue
Hello again. Finally the problem was the Akai. I took it to do a set-up, belts, lubrication, adjustments etc and some capacitors that were out of value. Now it works correctly and the recordings are heard perfectly on both the grundig and the Akai. Thanks to everyone for the tips
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15th Jan 2023, 11:33 am | #80 |
Dekatron
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Re: Grundig tk 23 L speed issue
Good news, well done.
David |