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Messages - analogfan

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Hello all,

Finely got the speed problem resolved.  The tape tension  idlers needed cleaning/lube, pulled the capstan servo board, checked it for bad diodes, caps, resistors, put the board back in, reseated the connectors, including one the was loose on the reel control board and carefully went through the alignment procedures several times.  The oscillator pot is near the end of its adjustment range but the speed issue is resolved for both fixed and variable speed.  I was surprised that there was quite a bit of interaction between the fixed speed alignment and the variable speed alignment as I thought the circuits were pretty much independent of one another.  Thanks to the forum for the advice.

QUESTION:  I found a "replacement" board for the capstan servo control board but while about 3/4s of it matched, the connectors were different.

The one in my RS1500US is Technics part #:  QJI0745RP

The replacement board (which I could not use) is Technics part #: QJI0745RP E  The "E" seems to be a later revision or for use in one of the other RS15XX family.

Does anyone know which Technics model (maybe a 1506 or 1520?) this board is used in?

Thank you, Bob Edwards

To the guy with the 1506 speed problem like mine, I am going to try going through the 1st few alignment steps including checking brake tension and the speed adjustment - please feel free to call me if you want to share ideas.  I will also look into the belt suggestion though I think it is a circuit issue as there are two different circuits with the manual speed adjustment and the standard speed circuit.  I doubt if it is a mechanical problem because it would show up either way.  No disrespect intended, just an old (really old) tech with (maybe) still good instincts.

Thanks, Bob Edwards/617 335-0066

Reel to Reel Tape Machines / Re: Technics 1500 Test Alignment Tapes
« on: February 21, 2011, 08:33:31 PM »
Thank you Steve.

I was aware of MRL but looking for other sources in case.

Best, Bob Edwards

Reel to Reel Tape Machines / Re: Technics 1500 brake pad check and clean
« on: February 21, 2011, 08:31:31 PM »
Wow Steve!  What a great reply.  I was totally intimidated by the reel motors & brakes.  Thank you for demystifying it for me!

This is a great forum!  Thank you again, I will post the outcome of the project.

Regards, Bob Edwards

Reel to Reel Tape Machines / Technics 1500 Test Alignment Tapes
« on: February 21, 2011, 02:45:53 PM »

I have speed problems with my 1500 (prior post) and need a test tape with about 10 minutes of 3 kHz tones at 7 1/2 IPS and 10 minutes of 3 kHz tones at 15 IPS to check wow and adjust the speed.  Is there a source for this?

How about the standard recording level, azimuth and freq. response tape for 71/2 & 15 IPS?  Does the Tape Project sell any test/alignment tapes?  Any other sources known?

The wow/speed tape is most pressing for me right now.

Thank you, Bob Edwards

Reel to Reel Tape Machines / Technics 1500 brake pad check and clean
« on: February 21, 2011, 01:31:30 PM »
Hello all,

I have cleaned the brake drums - I want to check my break pads.  It looks like there are two possibilities:

1. Back and top cover removed, unscrew the three phillips head screws holding the motor and carefully remove it through the top or move it to the side.  I am hoping the motor has a connector for the wiring.

2. Remove the runout bearing assembly at the rear, pull the C-clip on the end of the shaft at the rear and remove spindle/rotor assembly from the front.

clean the pads with a q-tip lightly with a naptha based cleaner (but don't soak the adhesive - I did read this on the forum I believe).

Are brake pads available from somewhere?

Sorry if this is on the forum somewhere - if it is, I could not find it.

Thank you, Bob Edwards

Reel to Reel Tape Machines / Re: Technics 1500 capstan motor speed problem
« on: February 07, 2011, 05:53:41 PM »
Thank you both, I will check out the switch as you suggested, hit it with Deoxit and go through the alignment.

More later, and thanks again!  Bob Edwards

Reel to Reel Tape Machines / Technics 1500 capstan motor speed problem
« on: February 07, 2011, 09:37:24 AM »
Hello there,

I have been bringing my recently acquired "cherry" 1500 back into the world.  Everything works well at this point after working the switches/controls and keeping it running on and off for a couple of week.  It sounds great, all controls work well, FF, Rewind, play, pause, etc. work fine.  The tape lifters work as they should, all controls work great (no drop-outs) and the tape path has virtually no wear and is clean as a whistle.  Pinch rollers have good pressure and do not slip.

The one issue is capstan speed in "Normal" that is, pitch control disengaged is a bit slow and getting flutter or wow (not sure which is which) per the strobe and listening.

With the pitch control on/engaged, the speed is locked in and steady as she goes, and adjusts to the proper speed (about middle of the pot range) and no speed issue at all.  I suppose I can use it this way but I have a bit of OCD!

I do not know if this is related (probably is) but the reel motors  (both) have more torque and turn more rapidly when the pitch control is on/engaged then when off.

I have looked at the circuit topology and the big difference I can see is that there is a quartz clock IC chip in the circuit with the pitch control off.

I have both volumes of the service manuals, a digital multi-meter, a freq counter and dual-trace Tektronics.  I was a radar tech many years ago and worked mainly on tube equipment, not much solid state.  If the IC is shot I hope I am not dead in the water as I know there are few parts around for Technics R2Rs.  I have not pulled the Techics apart yet.

Can anyone help or may have seen this problem before and can suggest a good place to start?  It is probably beyond my skills, so 2nd question is, can I send the capstan control board to someone for a look-see?

Thank you, Bob Edwards

Reel to Reel Tape Machines / Re: Technics 1500/1506
« on: January 26, 2011, 09:54:22 PM »
I understand that Pioneer vintage receivers have toggle switch covers that will work but I have not tried them.  Have read on other vintage sites.  Hope this helps and good luck!

Bob Edwards

Hello all,

I picked up a cherry 1500 (at least cosmetically), that runs slow on all speeds.  I can adjust the speed manually and it locks-in pretty well with just a bit of drift when 1st turned on.  If I leave the machine on and the capstan motor running for a couple of hours (use a rubber band to hold down the idlers) it will lock-in manually with virtually no drift - when I take it off manual, it runs slow at all speeds.  Any ideas?

Also, the tape lifters do not operate when tape is loaded (fast forward and rewind).  If I remove the tape and cheat the system by holding the idler down, the lifters work, but intermittently.  There seems to be dirty contacts in the right-hand idler assembly as sometimes I have to work it up and down to stop FF or reverse when I have things cheated (no tape loaded).  Also, any ideas?

The machine had been unused but otherwise well cared for.  Pots were noisy but worked them all manually 25 - 30 times as well as all of the front panel switches.  Sounds great on phones and operates well otherwise.  Tape transport controls and tape handling is otherwise excellent.  Brakes seem fine.  I have degaussed the heads, cleaned everything in the tape path with alcohol well, washed the rubber idlers rollers down with water - they seem to make good contact and do not appear to be slipping.  The heads are in excellent shape.   

I have not pulled it apart yet or used Deoxit on contacts or switches but probably will, given age of the machine and fact it saw little use.   

Otherwise, she is a beautiful thing!

Thank you in advance for any ideas/suggestions.  Regards, Bob


I have had the 1500  on for several days in a warm environment with the tensioners cheated and running at various speeds.  Continued to work all of the mechanical parts and the lifter problem has resolved itself.  BTW, I think the unit has been stored in a home environment and it does not have any bad odors or signs of abuse, smells good in fact, no signs of rust, and the more she runs, the better she plays and operates mechanically.

The speed issue persists however.  She locks in well with the manual speed control with little/no drift.  Still runs slow when the pitch/ manual control is out of the system.

I have both of the service manuals, a dual trace scope, a digital volt meter and a frequency counter.  Does anyone know of a source for the calibration tapes or a source that has the equipment to creat those required?  BTW, the 2nd volume of the service manual is EXCELLENT for the Technics 1500/1506!  I have to put a plug in for HiFi Engine where I obtained them!

I had an OTARI B3 and the alignment procedures were nowhere near as clear!

Thank you all for the support and suggestions!

RE: Tape Project mods for the Technics RS series - are any of the tape path mods available for a handy DIY guy like me?

Thanks again, appreciate your time and skills!  Bob Edwards

Thank you Tim,

What I mean is leave the tape as it was stored (packed), play or move the tape in some way onto another reel (un-packing) prior to baking.

I think I missed the point you clarified.  Appreciate your catching it.

Thank you for the feedback, appreciate it!

Regards, Bob 

Hi Docb and Ki Choy,

Thank you both for taking time to reply:

Doc, thanks for the feedback on the "kits" but I have to say I am disappointed, as I am sure others will be.  How bad are the fixed guides to do on a 5050 BIII, circa 1993?  Can the roller bearing swing arms be made available or is that also a major installation hassle?

Hello again Ki!  I have learned a lot about the 5050 recording/line out levels to consumer levels in the past few months and solved both of my problems which you helped me with early on.  Thanks for that!  If any one has this problem I am happy to share what I have learned.

Ki, thank you for the several methods to gently unpack the tape.  I am sure many others will be interested!

I don't have access to the a Studer but the other methods are good 2nd alternatives that I will try if I can get the un-packing question resolved as I found NEW INFORMATION (below ) on unpacking, attributed to Ampex/Quantegy.

Another point of view for all who are interested un unpacking tape before baking:

I ran across a paper on tape restoration (contains a lot of good information) as follows:

Title:  Magnetic tape deterioration: recognition, recovery and prevention, by Gerald D Gibson, Library of Congress,  Presented at the IASA Conference in Perugia, August 26, 1996

which states that Ampex/Quantegy both advise against unpacking because of print through.  Partially quoted as follows:

"Regardless of the time and temperature selected (for baking), do NOT, I repeat NOT, rewind the tape before baking as this will almost certainly increase print-through problems, according to Quantegy/Ampex...."

Soooooo, to unpack or leave packed, that is the question???

Any other points of view?

Anyone try a convection feature in a good electric oven for baking tape ?

Thank you, Analogfan, Bob Edwards

Any more word on the OTARI roller bearing guides and stainless steel roller bearing swing arm kit?

Thank you Analogfan/Bob Edwards

Thanks Tim,

I thought that was the answer.  I have seen the article but have not read it for awhile.

Are roller tape guides and swing arms with rollers available yet as a kit?  Seems to me I read something about the TP working on that. 

Will I have to go through an alignment procedure if I remove/replace the head block?  I think it comes off as a unit so the tape heads would not be moved?

Thank you again, appreciate your interest and time.

BTW, where are you located in the US?  I am in the Boston area.

Regards, Bob Edwards/Analogfan

The tapes I have to bake are Ampex 406/407.  The recordings were made '72 - '75 and the tapes have remained in the boxes, essentially unplayed, for many years.

Has anyone used a convection oven for baking tapes with good results?  I have a Jenn-Air electric oven with digital temp controls and the convection fan, built-in.   I also have an external digital thermometer i will use to track the oven temp.

RE: unpacking before baking - how critical is it?

I am concerned about unpacking them on my R2R for fear of losing more of the oxide.  I don't think I can run my OTARI at play speed without the tape contacting the heads.

Any comments would be appreciated.  Thank you, Analogfan/Bob/[email protected]

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