UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV 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.

Closed Thread
 
Thread Tools
Old 11th Feb 2023, 6:13 pm   #1
MrsSpock
Diode
 
Join Date: Feb 2023
Location: Dunoon, Argyll and Bute, Scotland, UK.
Posts: 3
Unhappy Philips N4308 Reel 2 Reel no sound?

Hi all!

I recently took in an orphaned N4308, sight unseen. I have a tape of my dad’s voice I’m hoping to hear again after 40 years 😊. So of course on opening I found lots of black grease everywhere and although the modulator lit up and the motor turned ok nothing else happened. After searching forums I realised the grease was the remains of the perished belts so these have been replaced. Now we have spin! However nothing plays. No movement of the needle, no crackle of a speaker. The tape moves over the head and there’s just silence..

I’m not an expert, not even a novice at electronic repairs. Can anyone advise me what I should do next? I have no testing equipment and just a screwdriver to my name. Does the head need replacing? Could it be the speaker? Just looking for hints from experts such as are on this forum. And the top three likely explanations.

Much gratitude.
MrsSpock is offline  
Old 11th Feb 2023, 7:04 pm   #2
Uncle Bulgaria
Nonode
 
Uncle Bulgaria's Avatar
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,314
Default Re: Philips N4308 Reel 2 Reel no sound?

If you've got an irreplaceable tape, I'd be very careful of putting it on an unknown machine - it could be erasing it as you go! There are members on here who will do you an excellent digitisation of any tape format you can mention, which would at least give you a backup before you delve into the tape machine. Put a message in the 'services wanted' section.

Is the tape in the right way round?

Searching the 'net shows the N4308 is a four-track mono machine. Do you know what format the tape recording is in? Here's some description of different ways the tape is used in different types of machine.

There's a manual available here. I have no experience with your machine, but perhaps checking the playback instructions would show some procedure you were unaware of. However, I'd advise against playing the recording until you know the machine is performing - get a throwaway pre-recorded tape from a secondhand shop for testing!

If you wish, with the help here you'll be able to repair your machine and no doubt be given plenty of advice to obtain test equipment...and you'll never look back!

Welcome to the forum!
Uncle Bulgaria is offline  
Old 11th Feb 2023, 11:21 pm   #3
MrsSpock
Diode
 
Join Date: Feb 2023
Location: Dunoon, Argyll and Bute, Scotland, UK.
Posts: 3
Default Re: Philips N4308 Reel 2 Reel no sound?

Thank you for the welcome. Good advice. I have a spare tape so not touching the precious one just yet!
I’ve got the insert manual but just don’t know where to start. As there’s zero crackling or noise at all I wonder if the speaker is dead.
I’ve tried all different settings and no dice sadly.
MrsSpock is offline  
Old 12th Feb 2023, 2:31 pm   #4
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

There are a multitude of potential problems that could result in no playback sound, it is not easy to advise, especially as you have minimal electronics fault finding knowledge/experience.

Are you happy that the tape is the correct way round ? for tape that is brown on both sides, the shiny side should contact the heads.

It is possible for the combined Playback/Record head to have failed (open circuited) but fairly unlikely. Have you tried recording then checking Playback ?

The needle on the VU meter only shows the signal in Record mode, so no needle response during Playback is normal (on some other different machines the VU meter wil show both the Record and Playback signals).

There could be an electronics failure, with a failure of a component in the amplifier circuitry or power supply circuitry. With a test meter set to measure DC voltage, it is fairly easy to test the power supply voltages if you know what you are doing. This would involve working inside the live machine so safety considerations are important.

It is possible to do a basic/crude check of the amplifier electronics by touching (with finger tip or screwdriver) the wires that connect to the Playback/Record head, in Play mode with high volume setting should get quite a loud hum from the speaker.

It is not impossible for the speaker itself to have failed (gone open circuit) but pretty unlikely. The speaker can easily be tested using a test meter to measure Resistance/Continuity across it (machine unplugged from electricity supply), it should measure a few Ohms/show good continuity. If the test meter is an old analogue type, the speaker will audibly click when meter is connected across it

On the rear panel there is a 2 pin connection socket for connecting an external speaker, if you had another speaker and a suitable cable connection (needs a 2 pin male DIN loudspeaker connector to plug into the 2 pin female connector at the machine) you could retest with external speaker.

When the 2 pin DIN connector is plugged in, it disconnects the internal speaker by operating a switch built into the 2 pin female connector. It is possible for the switch to have failed (gone open circuit), thereby disconnecting the internal speaker resulting in no sound, I have experienced this a couple of times.

Also on the rear panel is a connector for connecting headphones (a 5 pin 240 degree female DIN type), when the headphones are plugged in, a switch in this socket will also disconnect the internal speaker. So a failure of the switch in the headphones socket would also explain no sound.

David
DMcMahon is offline  
Old 12th Feb 2023, 3:38 pm   #5
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

If you have a microphone wired to a 3 or 5 pin DIN plug then could check recording to see if any signal on the VU meter (indicating that much of the amplifier electronics is basically OK). Also should hear (Monitor) the recording sound while recording with the volume control turned up.

Note - with microphone recording can get loud howling from the speaker at high record levels and volume turned up, especially if the microphone is close to the speaker area.

David
DMcMahon is offline  
Old 12th Feb 2023, 3:58 pm   #6
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

When machine is switched on, does the VU meter illuminate ?

The lamp for this (LP1 or LA depending upon which schematic) is fed with a reduced AC voltage supply that then is rectified to provide the various DC voltage supplies.

David
DMcMahon is offline  
Old 12th Feb 2023, 5:11 pm   #7
ben
Dekatron
 
ben's Avatar
 
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
Posts: 7,484
Default Re: Philips N4308 Reel 2 Reel no sound?

Common problem for this series of machines. The output and driver transistors develop 'tin whiskers' internally. search for that and 'N4307' and you'll find some more info.
__________________
Regards,
Ben.
ben is offline  
Old 12th Feb 2023, 6:38 pm   #8
Tim
Dekatron
 
Tim's Avatar
 
Join Date: Jan 2003
Location: Bradford on Avon, Wiltshire, UK.
Posts: 3,301
Default Re: Philips N4308 Reel 2 Reel no sound?

Quote:

Are you happy that the tape is the correct way round ? for tape that is brown on both sides, the shiny side should contact the heads.
Are you sure?
__________________
"Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."
Tim is offline  
Old 12th Feb 2023, 7:13 pm   #9
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,548
Default Re: Philips N4308 Reel 2 Reel no sound?

Quote:
Originally Posted by Tim View Post

Are you sure?
Yes agree....it was always the dull side when I was repairing tape recorders.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman.....
Sideband is offline  
Old 12th Feb 2023, 7:17 pm   #10
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

Yes agree, well spotted Tim, another senior moment from me !

Dull side to contact the heads, shiny side facing the front of the machine (for machines that sit horizontally).

David
DMcMahon is offline  
Old 13th Feb 2023, 12:25 am   #11
Martin Bush
Octode
 
Martin Bush's Avatar
 
Join Date: Jan 2015
Location: Oxfordshire, UK.
Posts: 1,906
Default Re: Philips N4308 Reel 2 Reel no sound?

I have one of these and the perished belt goo was everywhere. Have you managed to get rid of it all? In my machine it was like tar and wasn't just the belts. It is possible it is stopping something mechanical working properly. Probably not the cause of your problem but worth mentioning.

My machine is quiet (not silent) and, when I get time, I need to follow advice I received here about the transistors (see Ben's comment).
__________________
Is it live, or is it... no, it's live actually...
Martin Bush is offline  
Old 13th Feb 2023, 10:58 am   #12
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

If you (MrsSpock) are struggling with this then would suggest posting a request for help here -

https://www.vintage-radio.net/forum/...play.php?f=145

There maybe someone in your local area who could help.

David
DMcMahon is offline  
Old 13th Feb 2023, 6:22 pm   #13
MrsSpock
Diode
 
Join Date: Feb 2023
Location: Dunoon, Argyll and Bute, Scotland, UK.
Posts: 3
Default Re: Philips N4308 Reel 2 Reel no sound?

Thank you for all the advice! I now have a few things to try.
If not then I could try taking it to someone who knows what they’re doing!
Much appreciated.
Have a great day
L
MrsSpock is offline  
Old 14th Feb 2023, 12:05 am   #14
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

This is one Post (there are others) that references the potential tin whiskers issue.

https://www.google.com/url?client=in...vzZ7KrokprmEQs

David
DMcMahon is offline  
Old 14th Feb 2023, 12:12 am   #15
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

More interesting reading on tin whiskers Posts, there are many others.

https://www.google.com/url?client=in...Pn35uEokwf7irq

https://www.google.com/url?client=in...wjqrb5gBi1zIV7

https://www.google.com/url?client=in...LChEuZyXDZas60

https://www.google.com/url?client=in...Vh1dXubAelGBto

David
DMcMahon is offline  
Old 5th Mar 2023, 11:39 am   #16
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

Quote:
Originally Posted by DMcMahon View Post

Also on the rear panel is a connector for connecting headphones (a 5 pin 240 degree female DIN type), when the headphones are plugged in, a switch in this socket will also disconnect the internal speaker. So a failure of the switch in the headphones socket would also explain no sound.

David
I have very recently purchased a N4308 and see there are 2 versions of the schematic showing different arrangement for the headphones connector wiring.

The RER Service Data Sheet shows the headphones connector (Skt 5) activating the loudspeaker output connector (Skt 4) and wired to L13.

The Philips (CES Ltd) Service information shows the headphones connector (BU 5) activating the loudspeaker output connector (SK 6) but not wired to L13 or anything else. L13 (and associated L14) are not on this version of the schematic. There also is a note on this schematic stating that BU 5 is not wired. This seems strange, the service information is "Provisional Information" so maybe when this Provisional version of the Philips manual was produced, the headphones connector was being fitted but not wired ?

My N4308 headphones socket is wired.

David
DMcMahon is offline  
Old 5th Mar 2023, 12:01 pm   #17
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

Quote:
Originally Posted by Martin Bush View Post
I have one of these and the perished belt goo was everywhere. Have you managed to get rid of it all? In my machine it was like tar and wasn't just the belts. It is possible it is stopping something mechanical working properly. Probably not the cause of your problem but worth mentioning.
Looks like I am lucky with my N4308, all 4 drive belts are intact and look in good condition. Not powered up yet (as have to clean various gummed up levers), to see what the sound level is like.

David
DMcMahon is offline  
Old 11th Mar 2023, 11:14 am   #18
DMcMahon
Dekatron
 
DMcMahon's Avatar
 
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,587
Default Re: Philips N4308 Reel 2 Reel no sound?

Quote:
Originally Posted by DMcMahon View Post
More interesting reading on tin whiskers Posts, there are many others.

https://www.google.com/url?client=in...Pn35uEokwf7irq


David
Forgot to mention that this one is a Sticky Thread in the Components and Circuits category section.

David
DMcMahon is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 11:29 am.


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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.