Sony HMK-70 repair issue - UK Vintage Radio Repair and Restoration Discussion Forum

crohamblues · 14th Jul 2020, 6:40 pm

Hi

hopefully someone can assist. Ive just bought a really nice HMK-70 with speakers and box from a charity shop, its in really nice condition, tape and radio work well however the turntable has an issue. originally it worked, in fact it only turned off when the unit was turned off i.e. the start stop button didn't do anything. I removed the platter and have clearly upset something as now the motor runs, but sends the tonearm immediately to the end of the record where it sits there, kind of jams. I wonder whether its just an alignment thing, or something more sinister. I appreciate that this is kind of vague, would,d be great if anyone has had experience of these. thanks, Justin

Edward Huggins · 14th Jul 2020, 7:26 pm

It's possible that you may have knocked the tip off the stylus during your investigations - this would cause the arm to skid to the centre of the record.

crohamblues · 14th Jul 2020, 7:45 pm

Thanks Edward. No the stylus is all good. I think maybe my description is a bit confused. Essentially the start stop mechanism isn't working. The turntable spins as soon as the power is on, the start stop button doesn't do anything, the gears that control the arm movement dont return it to the start of the rest when it gets to the end.

Michael Maurice · 15th Jul 2020, 8:22 am

It's probably suffering from dried up grease and will need to be stripped, cleaned and re-lubricated. if you remove the turntable you will see a large cog, you should be able to turn it fairly easily by hand. Also check the trip pawl (google it) is able to move freely and is activated when the arm moves near the centre of the record.

Marconi_MPT4 · 15th Jul 2020, 2:40 pm

This a common problem caused by the turntable thrust bearing. Worth checking turntable height and the bearing as shown here:

Link https://www.vintage-radio.net/forum/...59&postcount=3

Rich

14th Jul 2020, 6:40 pm	#1
crohamblues Triode Join Date: Jul 2020 Location: Purley, London, UK. Posts: 23	Sony HMK-70 repair issue Hi hopefully someone can assist. Ive just bought a really nice HMK-70 with speakers and box from a charity shop, its in really nice condition, tape and radio work well however the turntable has an issue. originally it worked, in fact it only turned off when the unit was turned off i.e. the start stop button didn't do anything. I removed the platter and have clearly upset something as now the motor runs, but sends the tonearm immediately to the end of the record where it sits there, kind of jams. I wonder whether its just an alignment thing, or something more sinister. I appreciate that this is kind of vague, would,d be great if anyone has had experience of these. thanks, Justin

14th Jul 2020, 7:26 pm	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,335	Re: Sony HMK-70 repair issue It's possible that you may have knocked the tip off the stylus during your investigations - this would cause the arm to skid to the centre of the record. __________________ Edward.

14th Jul 2020, 7:45 pm	#3
crohamblues Triode Join Date: Jul 2020 Location: Purley, London, UK. Posts: 23	Re: Sony HMK-70 repair issue Thanks Edward. No the stylus is all good. I think maybe my description is a bit confused. Essentially the start stop mechanism isn't working. The turntable spins as soon as the power is on, the start stop button doesn't do anything, the gears that control the arm movement dont return it to the start of the rest when it gets to the end.

15th Jul 2020, 8:22 am	#4
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: Sony HMK-70 repair issue It's probably suffering from dried up grease and will need to be stripped, cleaned and re-lubricated. if you remove the turntable you will see a large cog, you should be able to turn it fairly easily by hand. Also check the trip pawl (google it) is able to move freely and is activated when the arm moves near the centre of the record. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

15th Jul 2020, 2:40 pm	#5
Marconi_MPT4 Heptode Join Date: Mar 2011 Location: Dorset, UK. Posts: 521	Re: Sony HMK-70 repair issue This a common problem caused by the turntable thrust bearing. Worth checking turntable height and the bearing as shown here: Link https://www.vintage-radio.net/forum/...59&postcount=3 Rich __________________ To an optimist a glass is half full; a pessimist half empty; an engineer twice as big as need be!