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Old 10th Feb 2010, 12:10 pm   #1
'LIVEWIRE?'
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Default TANDBERG Portable 41 (TP41)

Circuit diagram, Service manual, or any info. on the above, I would guess, late 60s, portable L/M/FM Radio, please. Reasonable costs covered, of course.
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Old 10th Feb 2010, 1:49 pm   #2
mickjjo
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Default Re: TANDBERG Portable 41 (TP41)

The Tandberg TP41 circuit and service manual PDFs are available towards the bottom of this page:-

http://sportsbil.com/tandberg/

I have one of those, lovely sets!

Regards, Mick.
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Old 10th Feb 2010, 3:40 pm   #3
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Default Re: TANDBERG Portable 41 (TP41)

A common problem with these sets is that the low voltage stabiliser originally used breaks down and causes instability and screeching. The faulty component, which resembles a glass diode, can usually be identified by a small amount of green goo which has leaked from around it on to the PCB. It can easily be replaced by a resistor and diode with a similar forward voltage as the original device.
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Old 10th Feb 2010, 11:03 pm   #4
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Default Re: TANDBERG Portable 41 (TP41)

Mick, thanks for the info. I didn't know about that website. John, I'll check that stabiliser. It may account for very low volume
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Old 23rd Feb 2010, 11:37 am   #5
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Default Re: TANDBERG Portable 41 (TP41)

John, the only stabiliser(regulator)diode I can see is D601(a 1N4743)in the Car adapter module, which I don't have. Unless I'm missing something, I don't see anything looking like a glass diode on the PCB. The Radio is to be used only as a portable. There is an intermittent fault, which is that it will be silent for a while, then burst into life, and, after a while, fade away again. This on all wavebands. At some time in the past something has caused the AM tuning gang to seize up solid at about mid-capacitance. Maybe whatever this is has caused the electronic fault. Any ideas/sugesstions as to a remedy for the latter problem??

Last edited by 'LIVEWIRE?'; 23rd Feb 2010 at 11:47 am.
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Old 25th Feb 2010, 8:38 pm   #6
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Default Re: TANDBERG Portable 41 (TP41)

Further to my post#5 above, silly me missed the regulator(D501), which, encased in a sleeve, looked like a capacitor! Anyway, when the radio stopped working, I checked this device, which read 150 Ohms both ways round. On the circuit diagram D501 is marked as an ST1.5, but in the parts list it states 'BA170' Having none of either I fitted a 1.8v Zener Diode(a NOS Blaupunkt spare part used in similar circuits in their car radios. I also replaced the original series resistor(4k7) with an 8k2. Job done-or so I thought, but instead of the voltage across the ZD being stable at 1.8v it varies from about that to some 2.9v as the Vcc is swung from about 6.5 to 12v, causing lack of stability on FM. Am I missing something? (only been repairing radios, etc for 38 years!!)
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Old 6th Mar 2015, 3:02 am   #7
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Default Re: TANDBERG Portable 41 (TP41)

From time to time I have seen the same question asked about Tandberg portable radios. “What is that stabiliser device in the output stage?” I too have wondered, ever since I first saw a TP41 with a burnt-out output stage and crystals beneath the open-circuit stabiliser. I worked in a hi-fi repair workshop back then in the 1970s and even then it was a mystery. I modified the biasing to a more conventional form.
Recently I repaired a Tandberg TTR1 which uses such a device. In this case it was working, but faded up gradually from cold just like a valved set. I replaced the “stabilyt” with a small LED (as has been suggested before in this forum) and the set then worked instantly. Out of curiosity I then measured the removed stabilyt – and my meter gave a negative reading! Further testing showed it to be a rechargeable battery!
I think that solves the mystery.
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Old 6th Mar 2015, 10:43 am   #8
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Default Re: TANDBERG Portable 41 (TP41)

Looking at that circuit again, the circuit symbol for that stabiliser (D501) is a battery (or, more correctly a single cell), so could presumably be replaced by a new cell (if one of the same size & type is still available) Some Goodmans Car Stereos used a rechargeable battery as memory back-up, and these used to leak, damaging the PCB, until a different type of battery was fitted, so I should have been aware of this back in 2010!
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Old 6th Mar 2015, 9:34 pm   #9
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Default Re: TANDBERG Portable 41 (TP41)

Some more info here:http://www.antiqueradios.com/forums/...hp?f=1&t=86453
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Old 26th Mar 2015, 1:36 pm   #10
JohnBG8JMB
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Default Re: TANDBERG Portable 41 (TP41)

Evening all.

The link for Tandberg TP41 circuit and service manual PDFs -

http://sportsbil.com/tandberg/

returns a blank page. Does any one have a valid link for service info for this radio please? I'd like to get mine going again.

Regards, John G8JMB
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Old 26th Mar 2015, 6:53 pm   #11
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Default Re: TANDBERG Portable 41 (TP41)

Here:
http://nrhf.no/Katalogark/TANDBERG%20TP-41-s.pdf
http://elektrotanya.com/tandberg_tp-.../download.html
http://elektrotanya.com/tandberg_tp-.../download.html
http://www.hifi-manuals.com/Tandberg/TP-41/downloads
(requires registration)
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Old 26th Mar 2015, 6:59 pm   #12
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Default Re: TANDBERG Portable 41 (TP41)

Check the speaker before doing anything else. The speakers in these are notorious and impossible to repair (impossible for me, anyway). I have two of these both with knackered speakers. It's a custom Tandberg design and a generic replacement won't fit.
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Old 26th Mar 2015, 8:34 pm   #13
roffe
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Default Re: TANDBERG Portable 41 (TP41)

Actually it's a Peerless K590TM.

Tandberg used loudspeaker units from Peerless,Goodmans,Seas,ITT,Rola,Audax,Heco,Philips and so on and a few exotic ones from Hokutone,Matsushita,Oshima Denki,Primo and HIF.
Despite the Tandberg stamp,it's always something they got from another loudspeaker manufacturer.

The only units that are said to be Tandbergs own are the early HT150,HT165 from the 40's.
Used in radios and early hifi loudspeakers.
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Old 26th Mar 2015, 8:39 pm   #14
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Default Re: TANDBERG Portable 41 (TP41)

Quote:
Originally Posted by roffe View Post
Actually it's a Peerless K590TM.
I didn't know that. It's a very unusual shape, being very thin from the back to the front, and I've never found another speaker that will fit in the very restricted dimensions of a TP41/TP43.
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Old 26th Mar 2015, 9:07 pm   #15
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Default Re: TANDBERG Portable 41 (TP41)

I guessed it was a Peerless unit, so thanks for the confirmation. Unusual dimensions aside, it looks a lot like the units Hacker used in their Sovereign III "family", and they were definitely Peerless.

There was every chance that Tandberg got the manufacturers to make loudspeakers to their specification, rather than just pick something from the standard catalogues - that's quite common in hi-fi, at least.

If the fault is a rubbing voice coil caused by gravity (as opposed to overheating), it is often possible to bend the chassis slightly to eliminate the problem. I've done that with great success to a decent number of Hacker sets (both Peerless and Celestion loudspeakers), though not yet needed to try it with the Tandberg sets.
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Old 26th Mar 2015, 9:20 pm   #16
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Default Re: TANDBERG Portable 41 (TP41)

No, the magnet shifts, either as the result of a shock or just through age. It's a well known weak point.
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