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Author Topic: technics rs1700 adjustments  (Read 3770 times)

Offline tandyman

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technics rs1700 adjustments
« on: April 07, 2010, 05:16:07 AM »
is there an easy way to get to the adjustment pots on the main board,please help,thanks.
johnc
sony tc-766, tannoy kensington spks, luxman turntable, sme, shure vmr, sugden ia4 amp, oppo player, sat radio.

Offline traf

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Re: technics rs1700 adjustments
« Reply #1 on: April 08, 2010, 02:37:25 AM »
remove bottom cover and you are there

Offline tandyman

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Re: technics rs1700 adjustments
« Reply #2 on: April 08, 2010, 01:50:45 PM »
now that was to easy.no fun. big thanks with egg on my face.
johnc
sony tc-766, tannoy kensington spks, luxman turntable, sme, shure vmr, sugden ia4 amp, oppo player, sat radio.

Offline mossfred

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Re: technics rs1700 adjustments
« Reply #3 on: May 10, 2010, 06:11:59 PM »
Would the same apply to the rs1506 bias and eq pots?
Fred

Offline ironbut

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Re: technics rs1700 adjustments
« Reply #4 on: May 10, 2010, 06:25:45 PM »
Hi Fred,

Welcome to the forum.
In a word,.. yup.
steve koto
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Offline mossfred

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Re: technics rs1700 adjustments
« Reply #5 on: May 11, 2010, 03:20:39 PM »
Thank you Steve. I bought a 1506 on Ebay supposedly set up  for quantegy 456 and recently serviced. Of course it wont record properly, bias and eq all over the place! It plays ok though and the transport is good. Any hints on setting it up would be appreciated or or might return it.
Regards
Fred

Offline ironbut

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Re: technics rs1700 adjustments
« Reply #6 on: May 11, 2010, 06:16:30 PM »
Hmm, that's strange that the bias and eq would be severely out of adjustment.
You do realize that the 1506 records in 1/4 track only right? (forgive me if this sounds out of line but I have no idea what your experience with magnetic tape is)
Also, why don't you outline how you determined that the bias and eq is off.
You should probably check with the seller to determine which front panel settings he's had the machine biased and eq'ed for.  Most techs will use the center (#2) settings for something like 456 but you never know.

One thing that I find very common with these used machines is that the sellers will state that the machine has been recently serviced but what has actually happened is it was serviced not that long before it went into storage for many years. Sometimes, the contacts on the pots, switches and internal multipin connectors will oxidize. You might try marking (or in this digital age, take a photo of) the adjustment pots and squirt a little contact cleaner into them and rotate back and forth a few times. Then put them back to the original settings and try it then.
steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
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Offline mossfred

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Re: technics rs1700 adjustments
« Reply #7 on: May 11, 2010, 07:49:16 PM »
Did a frequency sweep using all bias and eq settings and all 3 show large rises in frequency response in the high end and the left and right are very different. Another strange thing is that the eq affects whilst recording and the bias during playback. That is definitely not right!!
Fred

Offline ironbut

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Re: technics rs1700 adjustments
« Reply #8 on: May 11, 2010, 09:57:10 PM »
Hey Fred,

It does sound like something going on with the record section of the machine.
First, I'd check with the former owner to see if he has any knowledge about this. He may have tried to bias the machine himself or maybe worked on it and plugged the wrong multipin in the wrong socket. Anyway, it'll give you a chance to let him know you're having problems with it.

Do you have a service manual for it yet? If not, you might be able to figure out if it's a problem with the circuits or an adjustment problem by trying to do the adjustments yourself.
Make sure that the entire tape path is spotless. I can't tell you how often left channel imbalance can be fixed by proper cleaning of the guides and heads on this machine. The left channel is always the outermost part of the tape and because of the angles involved you have to be methodical to clean up underneath the head shield.
Past that, you should check out this detailed alignment and biasing procedure;

http://www.analogrules.com/basicalign.html#bias

Let us know how it goes.



steve koto
 Sony scd 777es(R. Kern mods)> Vpi Aires>Dynavector XX-2mkll>Bent mu>CAT ultimate>CJ premeir 140>Magnepan 1.6qr(Jensen xover)Headphone Eddie Current Zana Deux>AT ad2000,HD800 ,Metric Halo ULN-2 (battery powered),
 HE Audio Jades