Sony HMP 70 - UK Vintage Radio Repair and Restoration Discussion Forum

Mr dimples · 26th Jan 2017, 12:06 pm

I just bought a lovely Sony unit it all looks good but the platter makes a grating sound when trying to play vinyl. I cannot see any obvious points of contact. It's not a Garrard TT and it's a model without a tape deck.

The Reject button does not work, I wondered if the mechanism under the platter is loose and creating the noise? The previous owner replaced the belt, I wonder if they knocked something? The centre spindle is not greased, should it be? The platter is also slightly higher on one side with other maybe touching the deck.

Any help would be great.

The radio sounds gorgeous through its OG speakers.

ukcol · 26th Jan 2017, 1:12 pm

Quote:

Originally Posted by Mr dimples

The previous owner replaced the belt.....

Most turntables have a thrust washer (see picture) that can stick to the plater when it is lifted off and then gets lost. This, among other things, can cause the platter to sit low and foul other parts of the mechanism.

Mr dimples · 26th Jan 2017, 8:31 pm

Quote:

Originally Posted by ukcol

Quote:

Originally Posted by Mr dimples

The previous owner replaced the belt.....

Most turntables have a thrust washer (see picture) that can stick to the plater when it is lifted off and the get lost. This, among other things, can cause the plater to sit low and foul other parts of the mechanism.

Yes after wiggling the centre spindle I managed to free it.I then realised by making a makeshift washer it raised the platform which in turn engaged all the return mechanism and now it's fully operational bar a new stylus which is shot.

Thanks for the reply, I just need to sort out a crackle which comes from one of the speaker ports.

Maybe a quick clean if I am lucky

sp10mk11 · 27th Jan 2017, 9:21 am

This is a common problem on these decks at this age, Sony used a sort of fibre thrust pad for the spindle, as it ages it goes soft and the platter drops causing the grating you describe, you have cured it the only way I know how by using another washer.
This is a good sound system I hope you enjoy.
Gary
PS other than using switch cleaner on all controls, the "crackle" from one of the channels could be a leaking transistor which will be a bit more involved to sort out.

Mr dimples · 28th Jan 2017, 9:25 pm

New stylus arrived today and it now works a treat. The Crackling has stopped too... maybe they were just damp?

I found I can listen to DAB too by hooking up my Android phone which is cool.

Mr dimples · 29th Jan 2017, 11:24 pm

The crackling is back agh!!!
Will try the switch cleaner tomorrow from Maplins..
Failing that I will start checking soldering joints on speaker connectors if that is the right word for them,
Its only audible on low volume but when wanting to listen low in the evening its rather annoying...

I checked and swapped both speakers round and its the left channel that seems to be the culprit.
I guess actually its not the switches in this case ?

Does anyone have a circuit diagram or pic of the insides. I know hoe the dec slides out but thats as far as I have gone so far for the other issues above ^^^

Regards

Edward Huggins · 30th Jan 2017, 11:58 am

It does sound like you may have a "rustling" capacitor or failing transistor in the left hand channel. Not being sure of your skills level (based on some of the wording you are using) are you new to vintage electronics?

26th Jan 2017, 12:06 pm	#1
Mr dimples Retired Dormant Member Join Date: Aug 2016 Location: Woodley, Berkshire, UK. Posts: 4	Sony HMP 70 I just bought a lovely Sony unit it all looks good but the platter makes a grating sound when trying to play vinyl. I cannot see any obvious points of contact. It's not a Garrard TT and it's a model without a tape deck. The Reject button does not work, I wondered if the mechanism under the platter is loose and creating the noise? The previous owner replaced the belt, I wonder if they knocked something? The centre spindle is not greased, should it be? The platter is also slightly higher on one side with other maybe touching the deck. Any help would be great. The radio sounds gorgeous through its OG speakers.

27th Jan 2017, 9:21 am	#4
sp10mk11 Octode Join Date: Feb 2009 Location: Cornwall, UK. Posts: 1,275	Re: Sony HMP 70 This is a common problem on these decks at this age, Sony used a sort of fibre thrust pad for the spindle, as it ages it goes soft and the platter drops causing the grating you describe, you have cured it the only way I know how by using another washer. This is a good sound system I hope you enjoy. Gary PS other than using switch cleaner on all controls, the "crackle" from one of the channels could be a leaking transistor which will be a bit more involved to sort out.

28th Jan 2017, 9:25 pm	#5
Mr dimples Retired Dormant Member Join Date: Aug 2016 Location: Woodley, Berkshire, UK. Posts: 4	Re: Sony HMP 70 New stylus arrived today and it now works a treat. The Crackling has stopped too... maybe they were just damp? I found I can listen to DAB too by hooking up my Android phone which is cool.

29th Jan 2017, 11:24 pm	#6
Mr dimples Retired Dormant Member Join Date: Aug 2016 Location: Woodley, Berkshire, UK. Posts: 4	Re: Sony HMP 70 The crackling is back agh!!! Will try the switch cleaner tomorrow from Maplins.. Failing that I will start checking soldering joints on speaker connectors if that is the right word for them, Its only audible on low volume but when wanting to listen low in the evening its rather annoying... I checked and swapped both speakers round and its the left channel that seems to be the culprit. I guess actually its not the switches in this case ? Does anyone have a circuit diagram or pic of the insides. I know hoe the dec slides out but thats as far as I have gone so far for the other issues above ^^^ Regards

30th Jan 2017, 11:58 am	#7
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,340	Re: Sony HMP 70 It does sound like you may have a "rustling" capacitor or failing transistor in the left hand channel. Not being sure of your skills level (based on some of the wording you are using) are you new to vintage electronics? __________________ Edward.