Nakamichi BX300E take up reel problem - UK Vintage Radio Repair and Restoration Discussion Forum

theoldtrout · 15th Aug 2020, 4:39 pm

I've probably repaired about five of these machines [and probably a couple of hundred other cassette decks] all BX300's done by replacing the belts and the notorious idler tyre in these iffy Sanyo mechanisms.
I've bought a non-working machine for me to use at home and have solved the no audio output issue by replacing a shorted cap in the PSU [no -12V]. I've replaced the belts and tyre and given the machine a good clean/lubricate where required but the machine stops randomly due to the take up reel appearing to slow or stop; adjusting the reel motor current that is responsible for the take up tension makes no difference and the circuit that control it seems OK. The machine fast forwards several C90 without fault and the take up hub span for an hour with no cassette in the machine. There is plenty of torque when trying to slow the reel with a finger against it. Sometimes it will play for twenty minutes other times a few seconds and yes, I've tried different tapes.

I'm starting to run out of ideas on this one. Anyone had a similar fault not cured by the usual? Thanks, Angela

Michael Maurice · 15th Aug 2020, 9:56 pm

Hi Angela,

My first thoughts are: Where did you get the idler tyre from? Can you check that the take up spool is actually free to move?

May I suggest you put a voltmeter across the motor and see what happens when it slows down and stops.

The motor itself could also be faulty, the fact that it rewinds and fast forwards is due to the increased voltage supplied to it. If you can take it out and see if it rotates easily then that might also help you.

paulsherwin · 15th Aug 2020, 10:42 pm

I have found that a neoprene O-ring works better then a standard idler tyre. YMMV of course.

theoldtrout · 16th Aug 2020, 8:49 am

Thanks for the replies. The belts and tyre came from a supplier in Germany I've used many times before. The take up spool has been removed, spindle cleaned and re-assembled, it moves freely as does the motor. The tape transport is correctly aligned. The voltage across the motor is between 2.5 and 4 volts depending on the tape quantity on the take up spool. I'm going into the workshop this afternoon so shall watch the AVO with the machine running. Hope it isn't a dodgy motor, they are rare.

TIMTAPE · 16th Aug 2020, 12:52 pm

I'd check that Stop function is only caused when the take up table actually stops or close to it. On that model does the End of Tape function sense a stop at the actual take up table or is there a belt driving a separate unit?

theoldtrout · 16th Aug 2020, 4:56 pm

I seem to have it sorted but shall run a few tapes through tomorrow. Motor is OK, electronics driving reel motor OK. Auto-stop OK. Back tension OK, dual capstan OK. I re-soldered some joints around the reel motor circuit that looked dodgy. Also, found a cassette with a transparent body so that I could see through to the idler wheel and saw that it would slip in play mode. Removed the new tyre and compared it to the old and they are different sizes, only 1.5mm but enough to make a difference; Mrs Angry email to the supplier. As Paul Sherwin suggested I found an O ring the correct size and bingo! It works. I'll report back tomorrow. I seem to remember Sankyo also made the mechanism with gears instead of the tyre which is probably more reliable.

Michael Maurice · 16th Aug 2020, 5:05 pm

Can you PM me the supplier in Germany please? One of them gets very stroppy when you complain.

paulsherwin · 16th Aug 2020, 5:12 pm

I bought a new idler tyre for my BX100 and it slipped. I tried an O-ring as a temporary fix and it's still working 3 years later. Admittedly it doesn't see heavy use though.

theoldtrout · 17th Aug 2020, 6:58 pm

I forgot to take some tapes into the workshop to fully test this machine but here is a photograph of the troublesome idler.

jascha · 19th Aug 2020, 6:51 am

The o ring trick sounds fantastic

.
Any suggestions please where I can get the best belts for my Nak 582 (which I am yet to receive having just bought it from Germany)? The unit will definitely need know belts and from what I read online the only ones that are recommended have to come from Marrs in the USA which for us in the UK works out rather pricey. I will need to restore it back to its original spec performance wise and a good set of belts is a start. Any tips please from where I can source reliable belts?

Many thanks

Welsh Anorak · 19th Aug 2020, 4:38 pm

Does this use the RF-500 motor? These can stall at low voltages but run perfectly well at full pelt.

15th Aug 2020, 4:39 pm	#1
theoldtrout Hexode Join Date: Sep 2008 Location: Charlton Mackrell, Somerset, UK. Posts: 315	Nakamichi BX300E take up reel problem I've probably repaired about five of these machines [and probably a couple of hundred other cassette decks] all BX300's done by replacing the belts and the notorious idler tyre in these iffy Sanyo mechanisms. I've bought a non-working machine for me to use at home and have solved the no audio output issue by replacing a shorted cap in the PSU [no -12V]. I've replaced the belts and tyre and given the machine a good clean/lubricate where required but the machine stops randomly due to the take up reel appearing to slow or stop; adjusting the reel motor current that is responsible for the take up tension makes no difference and the circuit that control it seems OK. The machine fast forwards several C90 without fault and the take up hub span for an hour with no cassette in the machine. There is plenty of torque when trying to slow the reel with a finger against it. Sometimes it will play for twenty minutes other times a few seconds and yes, I've tried different tapes. I'm starting to run out of ideas on this one. Anyone had a similar fault not cured by the usual? Thanks, Angela

15th Aug 2020, 9:56 pm	#2
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: Nakamichi BX300E take up reel problem Hi Angela, My first thoughts are: Where did you get the idler tyre from? Can you check that the take up spool is actually free to move? May I suggest you put a voltmeter across the motor and see what happens when it slows down and stops. The motor itself could also be faulty, the fact that it rewinds and fast forwards is due to the increased voltage supplied to it. If you can take it out and see if it rotates easily then that might also help you. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

15th Aug 2020, 10:42 pm	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Nakamichi BX300E take up reel problem I have found that a neoprene O-ring works better then a standard idler tyre. YMMV of course.

16th Aug 2020, 8:49 am	#4
theoldtrout Hexode Join Date: Sep 2008 Location: Charlton Mackrell, Somerset, UK. Posts: 315	Re: Nakamichi BX300E take up reel problem Thanks for the replies. The belts and tyre came from a supplier in Germany I've used many times before. The take up spool has been removed, spindle cleaned and re-assembled, it moves freely as does the motor. The tape transport is correctly aligned. The voltage across the motor is between 2.5 and 4 volts depending on the tape quantity on the take up spool. I'm going into the workshop this afternoon so shall watch the AVO with the machine running. Hope it isn't a dodgy motor, they are rare.

16th Aug 2020, 12:52 pm	#5
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Nakamichi BX300E take up reel problem I'd check that Stop function is only caused when the take up table actually stops or close to it. On that model does the End of Tape function sense a stop at the actual take up table or is there a belt driving a separate unit?

16th Aug 2020, 4:56 pm	#6
theoldtrout Hexode Join Date: Sep 2008 Location: Charlton Mackrell, Somerset, UK. Posts: 315	Re: Nakamichi BX300E take up reel problem I seem to have it sorted but shall run a few tapes through tomorrow. Motor is OK, electronics driving reel motor OK. Auto-stop OK. Back tension OK, dual capstan OK. I re-soldered some joints around the reel motor circuit that looked dodgy. Also, found a cassette with a transparent body so that I could see through to the idler wheel and saw that it would slip in play mode. Removed the new tyre and compared it to the old and they are different sizes, only 1.5mm but enough to make a difference; Mrs Angry email to the supplier. As Paul Sherwin suggested I found an O ring the correct size and bingo! It works. I'll report back tomorrow. I seem to remember Sankyo also made the mechanism with gears instead of the tyre which is probably more reliable.

16th Aug 2020, 5:05 pm	#7
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: Nakamichi BX300E take up reel problem Can you PM me the supplier in Germany please? One of them gets very stroppy when you complain. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

16th Aug 2020, 5:12 pm	#8
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Nakamichi BX300E take up reel problem I bought a new idler tyre for my BX100 and it slipped. I tried an O-ring as a temporary fix and it's still working 3 years later. Admittedly it doesn't see heavy use though.

17th Aug 2020, 6:58 pm	#9
theoldtrout Hexode Join Date: Sep 2008 Location: Charlton Mackrell, Somerset, UK. Posts: 315	Re: Nakamichi BX300E take up reel problem I forgot to take some tapes into the workshop to fully test this machine but here is a photograph of the troublesome idler. Attached Thumbnails

19th Aug 2020, 6:51 am	#10
jascha Hexode Join Date: Nov 2005 Location: Kent, UK. Posts: 332	Re: Nakamichi BX300E take up reel problem The o ring trick sounds fantastic . Any suggestions please where I can get the best belts for my Nak 582 (which I am yet to receive having just bought it from Germany)? The unit will definitely need know belts and from what I read online the only ones that are recommended have to come from Marrs in the USA which for us in the UK works out rather pricey. I will need to restore it back to its original spec performance wise and a good set of belts is a start. Any tips please from where I can source reliable belts? Many thanks

19th Aug 2020, 4:38 pm	#11
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,925	Re: Nakamichi BX300E take up reel problem Does this use the RF-500 motor? These can stall at low voltages but run perfectly well at full pelt. __________________ Glyn www.gdelectronics.wales