UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players

Notices

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

Reply
 
Thread Tools
Old 13th Feb 2020, 12:54 pm   #1
nicola.ghinassi
Diode
 
Join Date: Feb 2020
Location: Bologna, Emilia Romagna, Italy
Posts: 5
Default Philips N4450 Reel to Reel Tape Player

Hello everybody, I'm new to the forum. I received a Philips N4450 as a gift, and I am proceeding to put it back into operation. I replaced all the belts, checked the contacts and circuits. Two problems: when I turn it on, there is a continuous background noise, I was unable to understand its origin. In addition, the REC key always remains on. Could it be the flip flop card and its transistors? Everything else seems to be working well. I am in your hands to ... find a solution.
Thanks in advance, Nicola
nicola.ghinassi is offline   Reply With Quote
Old 13th Feb 2020, 6:16 pm   #2
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,817
Default Re: Philips N4450 Reel to Reel Tape Player

A function 'stuck on' (like REC in your case) is very often due to the AC128s on the flip-flop boards.
TonyDuell is offline   Reply With Quote
Old 14th Feb 2020, 7:54 am   #3
julie_m
Dekatron
 
Join Date: May 2008
Location: Derby, UK.
Posts: 7,612
Default Re: Philips N4450 Reel to Reel Tape Player

BC327 will substitute OK for the AC128 in this case. It's a silicon device, but in this application only the PNP polarity is important.
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments.
julie_m is offline   Reply With Quote
Old 14th Feb 2020, 9:14 am   #4
nicola.ghinassi
Diode
 
Join Date: Feb 2020
Location: Bologna, Emilia Romagna, Italy
Posts: 5
Default Re: Philips N4450 Reel to Reel Tape Player

Thanks a lot for the reply, so I would say that I will proceed with the replacement of the AC128. The thing I noticed, when I start with the ON button, is that there is an annoying and continuous noise, like a bell trill, of which I can not find the origin at all. It is present both at standstill and when PLAY, FF, FW and PAUSE are started. In short, always .... any ideas? Thanks in advance, Nicola
nicola.ghinassi is offline   Reply With Quote
Old 15th Feb 2020, 6:26 am   #5
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,817
Default Re: Philips N4450 Reel to Reel Tape Player

There are two things that run all the time (when the machine is on) : The clock timer and the capstan motor.

You can disconnect the timer motor with the 2 push-on terminals next to it (these are 'live', so unplug the machine from the mains, disconnect the wires, then plug it in again). I seem to remember that the capstan motor is turned off in 'Amplifier' mode, so try selecting that with the slide switch.

Do either of those remove the noise?
TonyDuell is offline   Reply With Quote
Old 17th Feb 2020, 3:07 pm   #6
nicola.ghinassi
Diode
 
Join Date: Feb 2020
Location: Bologna, Emilia Romagna, Italy
Posts: 5
Default Re: Philips N4450 Reel to Reel Tape Player

I proceed to a check, as suggested. As soon as I have checked everything, I will let you know. thank you
nicola.ghinassi is offline   Reply With Quote
Old 2nd Mar 2020, 10:34 am   #7
nicola.ghinassi
Diode
 
Join Date: Feb 2020
Location: Bologna, Emilia Romagna, Italy
Posts: 5
Default Re: Philips N4450 Reel to Reel Tape Player

Hello everyone, solved the problem of noise similar to a "bell": disassembled the rotors, a nice clean thoroughly with alcohol, reassembled the belts. Otra only feels the engine running, nothing else. Unfortunately the old nails had completely melted, they got everything dirty, I had escaped the minimum residues from the first cleaning.
nicola.ghinassi is offline   Reply With Quote
Old 3rd Mar 2020, 9:20 pm   #8
Antonello
Diode
 
Join Date: Feb 2020
Location: Sassari, Sardinia, Italy
Posts: 5
Default Re: Philips N4450 Reel to Reel Tape Player

Quote:
Originally Posted by TonyDuell View Post
There are two things that run all the time (when the machine is on) : The clock timer and the capstan motor.

You can disconnect the timer motor with the 2 push-on terminals next to it (these are 'live', so unplug the machine from the mains, disconnect the wires, then plug it in again). I seem to remember that the capstan motor is turned off in 'Amplifier' mode, so try selecting that with the slide switch.

Do either of those remove the noise?
Tony in my 4450 Philips if I put amplifier mode the motor does not stop but starts to turn at very high speed. What could be the cause?

I have already changed the BD135 without solving. I replaced all transistors on the control board

If I disconnect the card and put the amplifier in mode, the motor remains off.
Antonello is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 9:01 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Copyright ©2002 - 2020, Paul Stenning.