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Author
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Topic: Bulb Issues
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Michael Clark
Film Handler
Posts: 95
From: Alexandria, VA U.S.A.
Registered: Mar 2005
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posted May 10, 2005 11:34 AM
Rick, thanks for all your help. Thank you to everyone who is kind enough to help think through this.
I followed the yellow wire from the side of the first microswitch and it led to the front of the machine (I had to remove the front panel), and it led right to the 2nd microswitch. Also, there was a white wire that ran from the transformer, and met up with the yellow wire, and then both ran to the 2nd microswitch. Then, on the opposite side of the 2nd microswitch, there was a white wire that ran directly to the bulb. And then a white wire ran from the bulb back into the center of the machine (couldn't see where it went). So it appears as though there are no fuses between the first microswitch and the bulb. Also, on the 2nd microswitch, I couldn't find a small reset button like I found on the first microswitch. Although maybe it's out of my line of vision. Does any of this make sense?
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 10, 2005 12:32 PM
Michael,
You've got yourself a weird one here, for sure. That white wire going to the inside of the machine from the bulb looks like it ends up on a printed circuit card that has the audio output circuitry as well as other impossible to define functions from the diagram. I suspect it's that same circuit board you took a picture of with the blue capacitor on it. You might, as Mike suggested, have a good look at that black device next to the blue capacitor. I can't make it out from your picture but I have seen small fuse holders of that configuration. I would be surprised if it were though since the lamp draws around 9 amps of current so the fuse would have to be healthy sized (around 10-15 amps I would suspect).
One quick question on the yellow leaded microswitc, Does that switch control the bulb on off or just dim it like high & low light output. I suspect from the wiring diagram that it may be hi & lo light output by the way it's hooked up to the transformer.
Rick
PS. Mike Peckham and I have been going back and forth via email on this. It sounds like your projector, at this moment, is completely dead, right? No power to anything and you can't get the motor to run. Please confirm. I would say, in the absence of any other fuses, it has to be your main fuse that you blew. That is usually somewhere close to the power entry plug and usually accessible from the outside of the machine.
Please let me know.
[ May 10, 2005, 02:48 PM: Message edited by: Rick Skowronek ]
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 11, 2005 07:59 AM
Hi Michael,
Mike Peckham and I have been emailing like crazy on this. Just to clarify, you do have motor function, correct? The rest is dead. Without a new projector lamp we don't really know if that part works at all.
If the motor does work then your problem is probably more major than a fuse. Here's why. The lamp receives it's power from the two microswitches you tracked. The one on the lower right with the yellow and red leads is a brightness switch. When you move that switch to the up position it puts lower voltage on the bulb which makes it less bright.
The other microswitch that went to the bulb has two functions. It is the primary switch to turn the lamp on when you turn on the main projector control. It's second function is when your projector is plugged in but not running is to supply a very low voltage to the lamp. Not enough to light it but enough to keep the strain off of it when you do start the projector. The thoughts were to help the bulb last longer.
In Mike's version and on his diagram, that was the function of that second fuse he has. By your tracking it is clear Sankyo decided to omit that fuse. It would not stop the lamp from working as that fuse is out of the picture when the unit is running. Unfortunately for you, when you pulled the bulb with it plugged in, you shorted out that small "keep alive" voltage. Normally all that would have done is blow that fuse. Since it's obvious you don't have that fuse it's anyone's guess as to what took the brunt of the short. That's why my question of whether the motor was indeed still functional. You would still have to have a main fuse (hard to find, but there somewhere) but that would take power totally away from the projector and nothing would work. There are basically three independant power sources in the projector with the exception of the common transformer. One for the motor, one for the sound system electronics and one for the lamp.
Now what? One good test would be to get a known good lamp. Plug it in (with the power cord disconnected of course). Then fire up the projector to see if the lamp does light. I suspect it won't but this would point us in the right direction. It may be a joint common power connection was blown on the main PC card which then also shut down the sound. May be fixable with some effort but probably not by a layman. If by some chance it wiped the transformer, then you have a 20+ pound boat anchor. It's kind of unlikely though if the motor still runs.
I would be happy to look at it at no charge if there's a way you could pickup shipping in both directions but that's up to you. I have the necessary equipment to test it. Let me know on the motor still running question as that's the hinge pin of all the above deductions.
Rick
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 12, 2005 03:09 PM
Well, guess we have it pretty well tied to an area. From the looks of your picture Michael, that's gonna be a real SOB to get at the bottom of that card since it sits above the the other card. I think if you could see under it, you would find a fairly small burned area that unfortunately acted as a fuse. It also looks like, from the pictures that it's difficult to even look back under the top and spot the white and 2 black wires coming in to their respective spots.
The Bar LEDs for the level also receive their power from the sound card power so they won't light either. The dead give away is no pilot light since it probably would light if there were any power at all on the sound card whether the circuitry was goofed up or not.Usually, the only thing that shuts down everything like all of the sound card would be power.
So, there you have it. You know pretty much where it is and what it is. Afraid the old ball, as they say, is in your court. Just be careful in getting at those boards if you decide to try. Another short or breakage could wipe some pretty bad stuff. Parts would be a devil (if available at all) to get and then you would have your boat anchor.
Last, I tend to agree with Kevin Clark on the lamp socket. It is highly unusual to see a short between the lamp pins just from wiggling the bulb out. Usually means something is wrong with the socket. Offer still stands if you don't have a local guy you can take it to.
Hope everyone enjoyed a long winded troubleshooting exercise. I know I did.
Rick
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 12, 2005 05:03 PM
Michael,
I appreciate your dilemma. It would end up costing you probably close to $60 or more for a round tripper. And, while certainly appropriate to try and resell, I'm sure you'd feel somewhat remiss trying to explain and the obvious amount of effort to repair same. You may not get even one bid for all your effort. If you have some level of soldering capability as well as a multi-meter to test voltages, I'd say give it a go.
With that said, you know I'm looking for a projector to get started. Believe me, I haven't lead you astray at any point. Would have loved for it to be something that you could've done. You can kind of blame Sankyo for removing the obviously needed protection that would have saved much of this situation.
If you are going to dump it, please let me know. I would be happy to give you something for the projector and pay for shipping it to me. Obviously, that won't recoup your loss but at least you know it's going to someone who knows what the problems are and will take the risk. Let me know what you think and if that sounds fair. Otherwise, good luck on it and really sorry for the problems caused by a problem lamp socket. Shouldn't have been that disastrous.
Regards,
Rick
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 12, 2005 07:53 PM
Kev,
I appreciate someone else in the pool but let's recap just to insure I'm not too far off base. I agree on the three supplies and confirmed that about 9 posts above.
First, we all agree I presume, that the AC voltage is present for the sound card (going to the sound card via the orange wire from the transformer). If it wasn't there then the low brightness function on the bulb wouldn't work. It also supplies that. The motor voltage is present from the transformer as it runs and is supplied to the Motor control board (which also serves as a main connection point for many circuits) but especially the bridge rectifier for the motor control as well as all grounding/common points for all three power circuits. Please take a close look at the wiring diagram provided by Mike Peckham. The orange power wire (13.5 volts AC) for the sound circuits goes directly to the Sound Card. See schematic for exact clarification. I presume the bridge rectifier for the sound circuit is located on that board.
Now, understanding that the short circuit was through the two pins of the lamp connection, there is only one place where all the commons meet up. The 0 volt tap from the transformer that provides the "ground/common" is located on the upper right corner of the motor control card (via it's black wire shown on the wiring diagram) and also connects to the lamp for it's common, including the 2.9 VAC "keep alive" voltage via the white wire from the lamp socket, to the same spot which is what actually shorted. The only place where something could impact any of the power for the sound card is there and only via the common. It could not get to the sound card in any way shape or form since the common is right there tied to the lamp common and the common transformer lead. The sound card has just another common wire from that spot to it's card (next to the orange wire on the sound card) also colored black.
What I'm trying to say is that there is absolutely no way for a shorted set of lamp leads to find it's way to the bridge rectifier of the sound card. The fact that the motor runs and the lamp lights and no pilot light on the sound card says that it isn't getting any power whatsoever. Yet, his low lamp is getting power which means the sound card is getting the "plus" 13.5 volts AC that it's supposed to. It's missing the common from the black lead from the Motor control board whatever in the short caused that.
If you have another explanation, I'd be happy to hear it.
Thanks,
Rick
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James N. Savage 3
Phenomenal Film Handler
Posts: 1375
From: Washington, DC
Registered: Jul 2003
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posted May 12, 2005 09:49 PM
Michael-
Sorry about your Sankyo troubles. I wish I had checked this thread earlier. I have two Sankyo ST-800 projectors. One is only for parts because....the sound went out on it!
I can't complain though, since I've had it since 1980 and played it all the time back then. I really got some good milage out of it. When the sound went out about three years ago, I sent it off to Atlantic Camera Repair in New York. After keeping it for about a year, they finally returned it to me and stated that they did not know how to restore the sound. So I just keep it for parts. I purchased a used Sankyo ST-800 after that, and it runs fine.
When the sound went out in my old machine, it had been showing some warning signs- sometimes the sound would just fade out during a run, but piddling with it, I discovered that I could restore the sound temporarily by pressing the "record" button for a few seconds (If you try this, make sure you turn the projector off first, as not to earase your sound track).
Eventually, the sound died and would not return ![[Frown]](frown.gif)
Unfortunately, I am TOTALLY USELESS when it comes to mechanics, such as fixing machines, projectors, etc., so I can't really help you there.
If you think you can figure any thing out by looking over my working Sankyo projector, you can contact me via E-Mail. I live just over the Wilson bridge in southern Maryland just outside of D.C., and I work in D.C., so let me know if I can assist. Also, you are welcome to any spare parts from my old machine, only I doubt it can help, since it suffers from the same problem.
Nick.
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Jan Bister
Darth 8mm
Posts: 2629
From: Ohio, USA
Registered: Jan 2005
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posted May 12, 2005 11:11 PM
Guess what JUST popped up on eBay? A Sankyo Stereo 800, being sold as defective/for parts but with working sound. Maybe this is something that one of you (Rick or Michael) wants to check out.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=7515768879&ssPageName=STRK:MEWA:IT
With that out of the way - James, when the sound on your first Sankyo started going out, did it become distorted in a particular way as well? If so, my guess would be that some transistor failed and a replacement should fix that right up. I'm a bit surprised that this Atlantic Camera place there couldn't figure it out, seems it's just down to pure electronics - maybe they were more adept at fixing the mechanical aspects of projectors.
Michael, have a look at the auction as well - there are plenty of good photos of the Sankyo being offered there, maybe you can spot visual differences between the eBay unit and yours? It might help confirm that your unit is (or isn't) indeed slightly different, in regard to non-existent fuses and such. It would really be too bad if your unit couldn't be fixed, so I'm rooting for everyone who's been in this helping you so far - if I knew more about electronic components and how they interact, I would, too - but Rick seems to have that part down pat. ![[Smile]](smile.gif)
Oh, and one more thing... James, why do you call yourself Nick? ![[Confused]](confused.gif)
--------------------
Call me Phoenix. *dusts off the ashes*
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James N. Savage 3
Phenomenal Film Handler
Posts: 1375
From: Washington, DC
Registered: Jul 2003
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posted May 13, 2005 07:22 AM
Jan- I was wondering if ANYONE was ever going to ask me that ![[Big Grin]](biggrin.gif) .
Actually, my first name really is "James". When the old 8mm forum crashed a couple of years ago and we all had to re-register our names and information, I had my wife fill everything out for me (we always blame the wife, don't we ![[Wink]](wink.gif) ). When the instructions advised to use your REAL name, she took it quite literally and put my full official name, even though I haven't ever really gone by the name "James", but Nick, from my middle name of Nicholas. I'm only "James" on official paperwork, or in very formal situations. Thanks for asking!
Also, in reference to the sound, the only problem I had prior to it going out was an occassional slight "pop" sound that would happen every 5 minutes or so, usually occurring after an hour of continuous movie showing. This went on for about a year, then the occassional fading, then complete loss.
As I mentioned before, I did put MANY miles on this machine before it did this, so I don't really have a complaint on the Sankyo and would still rate it #2 after the Elmo's.
"Nick" ![[Cool]](cool.gif)
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Rick Skowronek
Expert Film Handler
Posts: 120
From: Marietta Georgia USA
Registered: May 2005
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posted May 13, 2005 09:44 AM
Guys,
Just a little input on your particular Sankyo sound problems. I presume that you all still had your pilot light lit, meaning the board was getting juice, you were just losing signal somewhere in the sound path. I probably personally serviced well over a thousand tape machines in my early career. The problem you describe Nick is probably due to a dirty, slightly corroded record/playback switch. Since probably one of the least used functions on these projectors is the record, the switches would tend to corrode since no wiping action is going on. Virtually every part of the sound system ends up going through that switch including all playback capability. There are a couple of ways to keep it going better. First with either the projector off or a non-important reel on it move that switch into record 10-15 times. The contacts on the switch will tend to self clean. Also, pickup a can of switch contact cleaner at Radioshack, locate the switch and spray it down. Then move the switch 10-15 times and spray again. This will pretty much restore the switch to like new performance. A regular routine should be that everytime you've played several rolls through it, move that switch a few times.
Another problem that showed up in the 70 and 80s japanese electronics is capacitor dry out. Over time these capacitors would just stop functioning. They are used extensively in the signal path of these electronics. Obviously, that requires some fancy equipment and fairly extensive electronics knowledge. Probably isn't worth fixing unless you do. Can't tell you how many low or no sound problems I traced to those.
Regards.
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