Technics SP-10 Mk.II PSU voltages

johnm · 09:10 PM

Hi folks!

Hoping someone out there familiar with these turntables might be able to help.

I have completely recapped the external SH-10E PSU unit, as well as the deck itself.

On the PSU (whilst disconnected from the deck) I have set the two adjustment pots for 5V and 32.5V respectively, as dictated in the service manual. The 140V line has no adjustment pot. I just measured this rail and it reads 159V! Surely this is too high?

Am I supposed to take this reading (and indeed, set the 5V and 32.5V adjustment pots) with the PSU connected to the deck instead?

If not what could be causing the 140V rail to be so high? Our mains is a little high at approx. 248-250V - could that account for it?

Many thanks.

- John

johnm · 9th July 2011, 11:55 AM

P.S. The 140V line is unregulated, so I assume that once connected to the deck the 159V I am currently getting would likely decrease anyway? The voltage of C417 is 160V, so I'm worried about running that cap at its limit.

The 5V and 32.5V lines are regulated, so I guess it makes no difference if these are measured under load or not?

johnm · 03:59 PM

Just took the voltages again with the external PSU connected to the deck. The 140V rail now measures 149V so I guess (taking into account our high mains here, and the fact that rail is unregulated) all is well with that.

The 5V on the PSU measured 4.9V under load, so I tweaked that up to get 5V. Ditto 32.5V which needed a very slight tweak. I guess the newbie lesson here is to measure under load!

All working well

The only bad news is that the strobe has finally met its maker! Was looking at this LED mod (Post 5):

http://www.ls3-5a-forum.com/phpBB3/v....php?f=15&t=94

The poster mentions R1=2K11 - however it doesn't appear to be that value from the picture (red/brown/brown/red/black/yellow??!)

- John

jlsem · 9th July 2011, 11:21 PM

You could increase R422 slightly to get the correct 140 volts.

John

johnm · 10th July 2011, 11:28 AM

Thanks for that John - that's great

I'll try tacking some other values in there and see what happens. I might abandon the 140V line altogether actually and try one of the LED mods instead (the 140V line is purely for the neon bulb).

Cheers!

MellowFellow · 11th July 2011, 06:58 AM

John,

My French is not so good - do you know of, or are you able to make an English translation of the LED strobe mod?

johnm · 11th July 2011, 10:08 AM

Just stick that link into Google translate:

Google Translate

8th July 2011, 08:45 PM	#1
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Technics SP-10 Mk.II PSU voltages Hi folks! Hoping someone out there familiar with these turntables might be able to help. I have completely recapped the external SH-10E PSU unit, as well as the deck itself. On the PSU (whilst disconnected from the deck) I have set the two adjustment pots for 5V and 32.5V respectively, as dictated in the service manual. The 140V line has no adjustment pot. I just measured this rail and it reads 159V! Surely this is too high? Am I supposed to take this reading (and indeed, set the 5V and 32.5V adjustment pots) with the PSU connected to the deck instead? If not what could be causing the 140V rail to be so high? Our mains is a little high at approx. 248-250V - could that account for it? Many thanks. - John Last edited by johnm; 8th July 2011 at 09:10 PM.

9th July 2011, 03:50 PM	#3
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Just took the voltages again with the external PSU connected to the deck. The 140V rail now measures 149V so I guess (taking into account our high mains here, and the fact that rail is unregulated) all is well with that. The 5V on the PSU measured 4.9V under load, so I tweaked that up to get 5V. Ditto 32.5V which needed a very slight tweak. I guess the newbie lesson here is to measure under load! All working well The only bad news is that the strobe has finally met its maker! Was looking at this LED mod (Post 5): http://www.ls3-5a-forum.com/phpBB3/v....php?f=15&t=94 The poster mentions R1=2K11 - however it doesn't appear to be that value from the picture (red/brown/brown/red/black/yellow??!) - John Last edited by johnm; 9th July 2011 at 03:59 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Please Need Help, Technics SP10 mk II	hallcon83	Analogue Source	1	13th October 2010 04:00 PM
Improved PSU for Technics SL1210 MK2 and SP 10 MK2 (and others)	beetle	Analogue Source	21	19th January 2010 11:25 PM
Technics SP-10 speed problems	Stefanoo	Analogue Source	3	17th August 2008 10:05 PM
Technics SP 10 Speed Problems	rollinr	Analogue Source	26	21st June 2004 06:44 AM
TEchnics SP10 MK II Turntable	diyman	Analogue Source	15	17th December 2001 02:28 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

9th July 2011, 11:55 AM	#2
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	P.S. The 140V line is unregulated, so I assume that once connected to the deck the 159V I am currently getting would likely decrease anyway? The voltage of C417 is 160V, so I'm worried about running that cap at its limit. The 5V and 32.5V lines are regulated, so I guess it makes no difference if these are measured under load or not?

9th July 2011, 11:21 PM	#4
jlsem diyAudio Member Join Date: Jun 2003 Location: Dallas,TX	You could increase R422 slightly to get the correct 140 volts. John

10th July 2011, 11:28 AM	#5
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Thanks for that John - that's great I'll try tacking some other values in there and see what happens. I might abandon the 140V line altogether actually and try one of the LED mods instead (the 140V line is purely for the neon bulb). Cheers!

11th July 2011, 06:58 AM	#6
MellowFellow diyAudio Member Join Date: Apr 2007 Location: Australia	John, My French is not so good - do you know of, or are you able to make an English translation of the LED strobe mod?

11th July 2011, 10:08 AM	#7
johnm diyAudio Member Join Date: Sep 2003 Location: Hampshire	Just stick that link into Google translate: Google Translate

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)