The Mullard/Philips 400a - UK Vintage Radio Repair and Restoration Discussion Forum

JonSnell · 31st Mar 2020, 11:16 am

I was asked to look at this wireless set as it hummed badly and had poor Medium Wave reception.
I took a few photos during the process.
I removed the perforated hardboard back and the chassis is removed by removing the control knobs and then unscrewing the four fixing screws underside of the Bakelite cabinet.
The cabinet slides off quite easily revealing the internal and front of the scale and tuning cables. The loudspeaker stays attached to the cabinet, it a permanent magnet type, on the Mullard model. Unsoldering the loudspeaker wires allows easy removal.
I was shocked to see what had been done in the past, the main smoothing double can capacitor had been removed and the wrong type of capacitors were employed and with bits of plastic tape were made to insulate the connections and bits of wire "tied" them down.
The underside was no better, a capacitor had been cut out and a replacement fitted rather badly.

Time to get to work.

I fitted a new 50/50uF can capacitor in the original holes of the mounting clip but had to use silicon sealer to fill the gaps and make it look better. I replaced the blue capacitor underneath the chassis with one of correct value and allbeit smaller size, it made it easier to fit.

I removed all of the valves and tested them on my AVO 160, they all still read good so I re fitted them.

Powering up the wireless I got a feint sound, a little like the old days when Luxembourg used to fade out but didn't recover.
I noticed the two trimmers had been moved and proceeded to inject a 1550kHZ signal and trimmed as per the service sheet. Radio 5 live them came romping in and as I live against a hill, there is not a lot else I can pick up on Medium Wave. Long Wave, forget it.
Also there was no illumination on the frond dial glass, a couple of 6.5v 150mA incandescent MES bulbs cured that.
Reassembly was the reverse of disassembly and the customer has now collected a fully functioning Radio Set.

I hope you found this of interest.

JonSnell · 31st Mar 2020, 11:21 am

The RF alignment is quite straight forward. Here are a few more photos.

Herald1360 · 31st Mar 2020, 9:40 pm

Sounds like you're easily shocked

Not pretty or even tidy but the bodges probably gave a tired old set a few more useful years for little cost. The set obviously didn't die as a result.

Think of it in the same way as slapping a load of filler on a rusty 15 year old car in the late '60s!

JonSnell · 1st Apr 2020, 5:07 pm

Quote:

Originally Posted by Herald1360

Sounds like you're easily shocked

Not pretty or even tidy but the bodges probably gave a tired old set a few more useful years for little cost. The set obviously didn't die as a result.

Think of it in the same way as slapping a load of filler on a rusty 15 year old car in the late '60s!

Well it has lasted since the mid 70s but really shoddy workmanship, wouldn't you agree. I like things to be repaired to a reasonable standard. Taking the rust out first is the least a body repair shop will do.

Station X · 1st Apr 2020, 5:46 pm

Gentlemen. Please let's not have a discussion about car body repairs. They have nothing at all to do with this discussion.

The General · 1st Apr 2020, 7:35 pm

Yes, it's shoddy workmanship but not uncommon. I have a wartime civilian set which had a can capacitor rolling around inside, the joints insulated with bits of torn off Sainsbury's carrier bag. Mind you it only cost £1, I bought it from a bloke sat in a doorway who looked like a tramp and probably was one.

31st Mar 2020, 11:16 am	#1
JonSnell Hexode Join Date: Oct 2019 Location: Weymouth, Dorset, UK. Posts: 476	The Mullard/Philips 400a I was asked to look at this wireless set as it hummed badly and had poor Medium Wave reception. I took a few photos during the process. I removed the perforated hardboard back and the chassis is removed by removing the control knobs and then unscrewing the four fixing screws underside of the Bakelite cabinet. The cabinet slides off quite easily revealing the internal and front of the scale and tuning cables. The loudspeaker stays attached to the cabinet, it a permanent magnet type, on the Mullard model. Unsoldering the loudspeaker wires allows easy removal. I was shocked to see what had been done in the past, the main smoothing double can capacitor had been removed and the wrong type of capacitors were employed and with bits of plastic tape were made to insulate the connections and bits of wire "tied" them down. The underside was no better, a capacitor had been cut out and a replacement fitted rather badly. Time to get to work. I fitted a new 50/50uF can capacitor in the original holes of the mounting clip but had to use silicon sealer to fill the gaps and make it look better. I replaced the blue capacitor underneath the chassis with one of correct value and allbeit smaller size, it made it easier to fit. I removed all of the valves and tested them on my AVO 160, they all still read good so I re fitted them. Powering up the wireless I got a feint sound, a little like the old days when Luxembourg used to fade out but didn't recover. I noticed the two trimmers had been moved and proceeded to inject a 1550kHZ signal and trimmed as per the service sheet. Radio 5 live them came romping in and as I live against a hill, there is not a lot else I can pick up on Medium Wave. Long Wave, forget it. Also there was no illumination on the frond dial glass, a couple of 6.5v 150mA incandescent MES bulbs cured that. Reassembly was the reverse of disassembly and the customer has now collected a fully functioning Radio Set. I hope you found this of interest. Attached Thumbnails

31st Mar 2020, 11:21 am	#2
JonSnell Hexode Join Date: Oct 2019 Location: Weymouth, Dorset, UK. Posts: 476	Re: The Mullard/Philips 400a The RF alignment is quite straight forward. Here are a few more photos. Attached Thumbnails

31st Mar 2020, 9:40 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: The Mullard/Philips 400a Sounds like you're easily shocked Not pretty or even tidy but the bodges probably gave a tired old set a few more useful years for little cost. The set obviously didn't die as a result. Think of it in the same way as slapping a load of filler on a rusty 15 year old car in the late '60s! __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

1st Apr 2020, 5:46 pm	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: The Mullard/Philips 400a Gentlemen. Please let's not have a discussion about car body repairs. They have nothing at all to do with this discussion. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Apr 2020, 7:35 pm	#6
The General Hexode Join Date: Apr 2007 Location: Milton Keynes, Buckinghamshire, UK. Posts: 329	Re: The Mullard/Philips 400a Yes, it's shoddy workmanship but not uncommon. I have a wartime civilian set which had a can capacitor rolling around inside, the joints insulated with bits of torn off Sainsbury's carrier bag. Mind you it only cost £1, I bought it from a bloke sat in a doorway who looked like a tramp and probably was one.