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Messages - Phil_in_CA

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1
Tape Tech / Re: Bias for RMG - Technics 1506
« on: January 05, 2012, 06:57:21 PM »
Thanks for the reply, Tim.

Yes, "By the Book" I know.  I cut my teeth on Ampex AG-440 in the 70s but could never afford one, at my "Assistant to the Chief" pay grade! LOL!  Biasing them was a snap, as it was just a tweak...

Anyway, these Technics decks are a breed apart from the 440s.  I have the service manual and can say that the biasing procedure uses the voltage drop across a 1 ohm load resistor in the record head circuit.  All this does, unless I am asleep, is to put the machine back to factory spec's, which is not what I want; unless the TP pancake tape I have (SM468, I believe) could be optimized with one of the factory settings (bias 1,2,3).  Hmmmm, probably not; most likely not!

Maybe someone here will chime in with their best idea on how to bias the Technics 1500 to Tape Project Tape.

2
Tape Tech / Bias - Technics 1500
« on: January 05, 2012, 11:55:18 AM »
Hi Steve,

Finally got back to working on my 1500.  I am trying to bias my deck to take advantage of some reel ends that I got from the Tape Project, back when they were selling them...  I can't remember the type just now, but anyway, I was attempting to set the bias only to find that my machine won't peak!

When I rack the bias control from end to end, the output tracks from low to high, and never peaks.  It seems that the machine won't generate enough bias to actually over bias this tape...

I wonder, and it has been suggested to me, that the coupling caps are shot and there isn't enough bias reaching the heads to have a peak.  Does this speak to you?  I expected a peak at least at the high end of the bias setting.

I want to get this set up so I can record with my new heads and now it looks as if I am going to have a huge re-capping project on my hands first!!  Not something I am looking forward to, since I do not have a desoldering station... argh.  I hate reworking pc boards!  Removing components is my least favorite part of electronics.

Before I forget, I hope you have had a great holiday.  We stayed home, where it was warm and quiet...

TTYL,
Phil

3
Thank you, Charles, for the detailed repy!

I now have the Technics tweaked up and sounding pretty good.  I went to the trouble of reconnecting the head block back to the internal electronics and have set bias and EQ to match the Tape Project tape, so that I can record as well...

Phil

4
Hi All,

I have modified my 1500 to have a direct output to the Seduction modified for tape head input.  Now, I have new heads and need to do a touchup alignment, but wonder how you folks do that, now that the internal electronics have been bypassed?  I suppose setting levels is no longer an issue, huh??

I really appreciate anything you can suggest to this novice technician...

Phil

5
Service Resources / Re: D.C. area RTR repair and modifications
« on: April 03, 2010, 06:12:21 PM »
So, Steve, who is Mike?  The former CJ employee that is the go to guy on the east coast?  I have a friend with an Otari who needs his deck serviced... he is in Atlanta, but maybe would ship his 5050...

Phil

6
Service Resources / Otari MX-5050 repair in Atlanta, GA???
« on: April 03, 2010, 05:37:41 PM »
Hi everyone,

I am trying to help a friend who has an Otari that needs service.  Is there anyone here who knows of a reliable serviceman in the Atlanta area?

Thanks in advance!

Phil_in_CA

7
Reel to Reel Tape Machines / Re: Maintenance tip for Brakes
« on: June 03, 2009, 06:04:04 PM »
Just a thought... another replacement for the felt pads was found to work well.  ?" cork with self adhesive.   Can be found at craft stores, or so I've heard.  YMMV.

8
Reel to Reel Tape Machines / Re: Chinese tape project
« on: April 28, 2009, 07:17:02 PM »
I found this:
http://www.perfectmusic.cn/En/Index1.html
but it seems to be dead, with only a few links still up.  The contact information link is 404, I am sorry to report.  I would sure like to know more about them and their product.

Phil

9
I appreciate all the suggestions.  Here's what I have done, in no particular order:
  took the head block off and back on to get the LED functioning again :)
  made sure I had the correct input connector ;2)
  jiggled, jimmied, juked, and clicked all the switches on the front whilst in record... all to no avail  :(
  I used headphones so that I could hear the input on source, but nothing off the tape  :(  Yes, the record light was lit...

I an going to disassemble the bottom panel and try to get at the connectors and switches. 
I have been waiting for the Service Manuals to arrive on CD from Paul Stublebine, who was nice in offering to send them to me.
BTW, I emailed JRF and inquired about sending my head block in for evaluation and a quote...  If I can just get a replacement playback head, that will have to do for now.  Also, I am planning on getting a Seduction preamp to modify for tape head input and I suppose that will make the record problem a moot point, huh?  I am harboring the crazy notion that there must be a way to set this thing up so that I can use the Seduction and STILL have a way to record.  (I want to do some archiving at 15ips...)

Enough for tonight, it is time for bed.... I got some room on the bench for the 1500 and left over room for a Seduction kit in the future.

Thanks again!

10
Well... (gulp) I guess I'll email Mr. French and arrange to send it to him and see what happens.  Also, I think I'll email Paul Stubblebine (I got the 1500 from him) and see if he has another head block that might be better than this one.  If he does, and I can afford it, then I will have a spare.

Then after that, I have to dive into the record electronics... it isn't recording correctly, and no matter how bad the  heads are, there should be some signal recording to tape.  The right channel is dead on record and the left might as well  be; I can barely hear the program material coming off the tape.  Playback is not too bad from pre-recorded tapes in either ?-track or ?-track, thankfully.

Thanks for your input, Steve.

11
Hi Steve,
Thanks for your reply.  Do you have any idea what new heads would go for??  I see an entire head assembly, but the owner isn't listing a price.  Probably wants to get MAX $$...requires an offer be made just to get a response!

I have run the machine for maybe an hour and didn't notice anything that sounded bad, like ticks, pops, clunks, rattles, etc.  Everything in the tape handling seems up to snuff.  When I attempted to record, however, even though the line input seems completely normal, the tape monitor reveals no signal on the right channel and precious little from the left but just enough to know that there is some signal there (more than 20 db down...).  It is clear that there is something compromised in the record circuitry.  Time to drag out the o'scope...

Thanks again, Steve.

Phil

12
Well, after doing so sleuthing on the internet (mainly the JFR Magnetics site) and reviewing the pictures I shot of the heads, it seems clear that this tape machine was used (endlessly) with the heads out of adjustment.  If I am wrong, please straighten me out on this...(pun intended)  And it also seems clear that the heads are shot, because you can see the gap is clearly visible and it is thicker at the bottom than at the top.  I don't understand how the gaps  are tilted in relationship to each other and the wear pattern looks different top and bottom...  the only thing I can think of is that the tension was greater on the bottom of the head then the top??!  This is all strange to me and anything you can do to teach me about this would be super.

I would appreciate any response you'd care to make (I am already in my flame retardant jumpsuit).

Thanks for your feedback, folks!

Phil

13
It was a pleasure to be in the company of so many "like minded" folks last weekend.  I can only hope that the aura will last for quite a while, or at least until I get invited the the next gathering...  And, thanks for all the great conversation.

I did turn the spring-loaded guides to an unflattened spot and even slightly loosened and turned the others. Thanks for the tips and the link.  I have a scope but don't have a tape, so I will have to invest in a tape and probably have to have the heads replaced.

A couple of things have happened since I posted. The strobe LED has died and I wonder if it has anything to do with my putting DeOxit on the connector pins... I will have to take the head nest back off and see if anything changes when I replace it.  Also, the head nest seems to be sitting a bit off to the left on the bottom, and I noticed it when I replaced it because it is close to the reversing pulley on the left side, not centered above it.  I am not sure this is making sense... yikes.  Anyway, I tried to loosen the three hex head screws and center the head nest, but it didn't seem to have any play.  It might have been crooked to begin with and I didn't notice?  I guess so.

Is this thread in the right place?? I would have thought that there would have been more views and replies...

14
Hi everyone,

I have just gotten a 1500 that needs some serious attention.  Thankfully, it seems like everything is on this machine, but boy is it filthy!  When I took the head nest off I almost fainted!  There was so much grunge under there that I wonder if the machine spent some time outdoors...

Anyway, I have a couple of concerns and want to get some suggestions about how to handle them.

  • the "guide pins" (just above the capstan) are corroded and I want to disassemble them to clean them, but worry about alignment. I tried a toothbrush and alcohol but they still look etched and ugly.
  • the head switch is gunky and should be disassembled, cleaned, and reassembled. It seems like someone stuck a pizza in the head assembly then reached in with their finger and tried to flick it out... I AM NOT KIDDING... (I have pictures!) Any tips?
  • the tape guides at the bottom of the path (next to the reversing roller) are worn flat and one has a slot cut into the flange next to the chassis.  Can I just rotate these to a non-flat area of the post and re-tighten?
  • the heads are so worn that there are slots cut into the faces where the tape wore them down. If I want to replace them or have them relapped, won't I have to have the entire machine realigned?  I think I already know the answer to this one, but...
There is more, but I don't want to overwhelm anyone who may innocently come across this post and swoon at their computer!

The good news is that I loaded a junk reel on the machine and all functions seems to work as far as tape shuttling are concerned.  The playback amps function, it changes speed, the meters seem to work (if slightly misadjusted) and light up, IT IS JUST filthy and needs some TLC.

Any comments, suggestions, or directions would be gratefully accepted.

Thanks one and all!
Phil

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