Philips GF732 Record player restoration - UK Vintage Radio Repair and Restoration Discussion Forum

nibbell · 6th Sep 2020, 5:01 am

Hi all,

I have been given a vintage record player by my grandmother and I've made it a project of getting it working. It is a Philips GF732 briefcase-style machine, with two detachable speakers as the case. After figuring out how to switch it on, the first issue I noticed is that the platter was not rotate. Searching the internet yields no information on this particular model, however following posts from this forum I found that the motor simply needed lubricating. The motor now spins.

Next issue, after cleaning and putting back together, I have discovered after connecting the speakers for the first time that they hum. Loudly. The hum is not related to the volume knob, it doesn't get more loud or quiet when changing the volume, and the hum means you can not hear the record play.

It is (from info I've gathered here) a mains & battery operated system, mains being the motor and battery for the rest. I have borrowed a Fluke T5-1000 multimeter, and although I don't know exactly if I am using it right but I think some of the transistors may not be good. Recalling the first few times I switched the record player on, there was a faint smell of burning.

I am a totally rookie regarding record players and electrics, any advice on fixing this hum would be greatly appreciated. I do not have and can't find the service data available anywhere online, but if there is anything you need from me to assist me let me know. Thanks

paulsherwin · 6th Sep 2020, 10:04 am

The PSU electrolytic capacitors are probably bad causing the humming (the two big aluminium cans on the top right of your fourth picture). Unfortunately there may be other bad electrolytics in there too, especially after spending 50 years in the Aussie climate, though those Philips blue sleeved ones do last quite well.

If you are getting sound out of both channels then there are unlikely to be transistor faults.

ms660 · 6th Sep 2020, 10:59 am

Schematic and layout info here:

https://archives.doctsf.com/document...0320&ref=29662

Lawrence.

Sideband · 6th Sep 2020, 11:52 am

Quote:

Originally Posted by nibbell

Hi all,
It is (from info I've gathered here) a mains & battery operated system, mains being the motor and battery for the rest.

?? Not according to the circuit it's not! Mains only which seems perfectly normal for a player of this type. Where did you get the idea that it was both?

Standard power supply arrangement where the motor runs directly from the mains and the transistor amplifier from a low voltage secondary winding with a normal bridge rectifier from a mains transformer.

ben · 7th Sep 2020, 1:46 am

I repaired the mono version of this model a few years ago. They use germanium transistors, which can go leaky. Do not run it in this state, the one I did had a damaged transformer due to the previous owner having done this.

One thing you cna try is to unclip and therefore isolate the transistors from the heatsink then briefly power it up and see if the hum is lessened or gone, and you get audio. If you do then the transistors will need changing.

Bear in mind that the cartridge in these tends to die with age and may also give no or low sound. These are a proprietary fit and could end up costing more than the player is worth to replace. But we can cross that bridge when we come to it.

nibbell · 8th Sep 2020, 4:30 am

Thanks for all the replies

I will need to do some learning regarding all these electrolytics as I've never done anything like this, unsure how I would even go about unclipping transistors.

It's a big job for me at least, and hopefully not too expensive. The cartridge looks good to me, it has had a plastic cover over while in storage

6th Sep 2020, 5:01 am	#1
nibbell Diode Join Date: Sep 2020 Location: Perth, Western Australia, Australia. Posts: 2	Philips GF732 Record player restoration Hi all, I have been given a vintage record player by my grandmother and I've made it a project of getting it working. It is a Philips GF732 briefcase-style machine, with two detachable speakers as the case. After figuring out how to switch it on, the first issue I noticed is that the platter was not rotate. Searching the internet yields no information on this particular model, however following posts from this forum I found that the motor simply needed lubricating. The motor now spins. Next issue, after cleaning and putting back together, I have discovered after connecting the speakers for the first time that they hum. Loudly. The hum is not related to the volume knob, it doesn't get more loud or quiet when changing the volume, and the hum means you can not hear the record play. It is (from info I've gathered here) a mains & battery operated system, mains being the motor and battery for the rest. I have borrowed a Fluke T5-1000 multimeter, and although I don't know exactly if I am using it right but I think some of the transistors may not be good. Recalling the first few times I switched the record player on, there was a faint smell of burning. I am a totally rookie regarding record players and electrics, any advice on fixing this hum would be greatly appreciated. I do not have and can't find the service data available anywhere online, but if there is anything you need from me to assist me let me know. Thanks Attached Thumbnails

6th Sep 2020, 10:04 am	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,944	Re: Philips GF732 Record player restoration The PSU electrolytic capacitors are probably bad causing the humming (the two big aluminium cans on the top right of your fourth picture). Unfortunately there may be other bad electrolytics in there too, especially after spending 50 years in the Aussie climate, though those Philips blue sleeved ones do last quite well. If you are getting sound out of both channels then there are unlikely to be transistor faults.

6th Sep 2020, 10:59 am	#3
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Philips GF732 Record player restoration Schematic and layout info here: https://archives.doctsf.com/document...0320&ref=29662 Lawrence.

7th Sep 2020, 1:46 am	#5
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Philips GF732 Record player restoration I repaired the mono version of this model a few years ago. They use germanium transistors, which can go leaky. Do not run it in this state, the one I did had a damaged transformer due to the previous owner having done this. One thing you cna try is to unclip and therefore isolate the transistors from the heatsink then briefly power it up and see if the hum is lessened or gone, and you get audio. If you do then the transistors will need changing. Bear in mind that the cartridge in these tends to die with age and may also give no or low sound. These are a proprietary fit and could end up costing more than the player is worth to replace. But we can cross that bridge when we come to it. __________________ Regards, Ben.

8th Sep 2020, 4:30 am	#6
nibbell Diode Join Date: Sep 2020 Location: Perth, Western Australia, Australia. Posts: 2	Re: Philips GF732 Record player restoration Thanks for all the replies I will need to do some learning regarding all these electrolytics as I've never done anything like this, unsure how I would even go about unclipping transistors. It's a big job for me at least, and hopefully not too expensive. The cartridge looks good to me, it has had a plastic cover over while in storage