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Author Topic: RS-1500 clean up struggles, SUGGESTIONS PLEASE...  (Read 8136 times)

Offline Phil_in_CA

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RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« on: March 17, 2009, 07:36:03 PM »
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

Offline ironbut

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #1 on: March 17, 2009, 09:43:43 PM »
Hi Phil. Great meeting you on Sat.. It sounds like you're really in for it with this machine. One good thing about hanging out with a bunch of modifiers, there's always parts laying around. It sounds like those guides may be pitted/rusted and and if so, you should try to get away from reusing them. Someone around here may have some spares you could get. I'd advise you to send that headblock to John French to have it checked out. You can probably save a little money by cleaning it up the best you can (the switch has silver contacts so it should be retrievable) and replacing or providing decent guides to John. If you want some info about heads and such, there's a guide in a sticky above the General forum with illustrations of what to look for with worn heads. John will visually align the heads which means that he can do pretty much everything except the adjustments like azimuth which are done with a scope on your output.
The bottom guides are actually spring loaded so you should be able to push them in and rotate them to an unmolested spot. You need to use a magnifier and a strong light to examine all of these spots where the tape makes contact. Just one little spur could really do a number on every tape you run across it. Pits are really just as bad since they collect debris like a rock in a river and an inie slowly becomes an outie.
One of the bottom lines with this and many other machines is going to be the deck plate. After you pull of the headblock, and before you bother doing anything else, put a straight edge across the top to be sure that it's flat (a few times across the width and height should do). It's made of pretty heavy alloy but if it's been abused to the point that it's bent at all, it's a write off. Everything attaches to that piece and must be carefully aligned referenced to that deck plate.
Here's John French's site;
http://jrfmagnetics.com/
steve koto
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Offline Phil_in_CA

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #2 on: March 18, 2009, 09:59:45 PM »
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...

Offline Phil_in_CA

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A picture worth a thousand words... Yikes!
« Reply #3 on: March 22, 2009, 09:02:57 AM »
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
« Last Edit: March 22, 2009, 09:20:19 AM by Phil_in_CA »

Offline ironbut

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #4 on: March 22, 2009, 10:16:05 AM »
Your right Phil. Those heads are probably shot. The good news is that I've certainly seen worse. The uneven wear comes from the heads being tilted a tiny bit or if that bottom head (record head) is worse than the others, it from uneven wear on the guide you just rotated. You probably wouldn't see this uneven wear if the previous owner had simply rotated those guides when they started to get a tiny bit flat spotted. But, most folks are don't know how simple it is and once things get flattened, the wear from the tape starts to align the tape path on it's own.
At this point, I think that you should proceed with your cleaning up program and afterwards, play some junk tapes  for a couple of weeks with it. If it seems ok and nothings begun to get noisy, then I'd send the headblock off to JFR for evaluation and an estimate. But before sending it off, really give that thing a workout and listen to it in a quiet environment paying attention to bearing/motor noises and the likes. And if your up to it, open up the back and top plate and see if there's any rust in there. If there is, let us know (it might not matter).
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 Phil_in_CA

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #5 on: March 22, 2009, 02:08:34 PM »
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

Offline ironbut

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #6 on: March 23, 2009, 01:02:21 AM »
Hi Phil, those head blocks can go for outrageous amounts. A reasonable amount for a complete block with unknown head condition is under $200. I saw a new one complete for over a thousand bucks! The least I've seen a new one go for was $750 (which is what I paid for my entire machine) but that was a couple of years ago.
I've never gotten an estimate from JFR on replacing the record head but you should be able to get new heads for about $200 each but they may not be exactly the same. They might be better actually. The Technics/Otari original heads are pretty soft so they wear pretty quickly. I know John French bought the entire stock of Nortronics when they closed shop. So, the only way to really know is to send it to him for an estimate. He may be able to salvage one or two heads (erase, 2 track, 4 track ?). You can guess all day about this kinda thing and still be shocked or delighted once he gets his hands on the headblock.
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 Phil_in_CA

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #7 on: March 23, 2009, 05:07:15 PM »
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.

Offline ironbut

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #8 on: March 23, 2009, 06:06:48 PM »
Just so you know, there's two different sets of inputs on the back of the Technics. One is marked thorough out (top=left channel, bottom=right channel) and the other is marked line in (same channel configuration). You should use the line in and not the through out. Other than that, as long as the record mode switches are down, it should record.
Is the red record light on the record button lighting up?
Also, have you tried working those record mode switches up and down while recording? They may just be all gunked up from non-use and not making proper contact.  Same for the eq and bias switches, the line level and mic level knobs (the mixer is before the record amp in the circuit). All of these should be done with a tape recording so you can go back and see if any of this exercising made any changes to the sound. You may be able to get at some of those switches by taking the side panel off and try squirting a little Deoxit into them. Remember, these controls may not have been touched by the original owner so they may have been in the same position since the '70's. I'd try all these low tech things first then check the multipin connectors that go to the bottom board (main board) .
Oh yeah,.. you said the strobe stopped working too. I'd check the continuity of that multi pin connector (maybe first) since I've never seen one of those strobes go out. It could be either end of that plug or where that wire bundle ends up.
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 Phil_in_CA

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Re: RS-1500 clean up struggles, SUGGESTIONS PLEASE...
« Reply #9 on: March 23, 2009, 10:54:22 PM »
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!