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Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2005 - 04:56 am: | 
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Hello,
I have one Yashica Electro 35 GTN, in very good condition, with interesting defect.
Ligt metering works well, except low light and diaphragm 8-16. My YE is unable in this conditions hold longer times than approx. 1-2 sec.
Because I'm experienced in electronics, I measured Yashica's circuits. Result is: one of transistors contained in simple integrated circuit is "weak". It have too small empowering factor.
My question is: Is possible to get good (new or good old) integrated circuit ? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2005 - 07:27 am: |
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Probably not, only from a junker. The GTN is the last generation which seems to have a monolithic integrated circuit. The main difference between generations of the Electro (E35, E35G, E35GS/GT and E35GSN/GTN) is the circuitry which changed from a tiny pcb board with a plastic housing over a hybrid module to the IC.
I think I still have a GSN (same as GTN but chrome) junker, it still should have its circuit. It arrived with a severely damaged lens so I did not check the meter circuitry.
Nice to meet a colleague from the electronics business... |
Roger Provins
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2005 - 12:20 pm: |
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I have just looked through my junk boxes and there is a Yashica GTN circuit board. Can you identify yours is any way? This one has EN408 and 2E 913 on the white board and 476 and 182 on a couple of the components. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 06, 2005 - 03:34 am: |
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Thank you for help. I will open my YE and identify type of PCB ASAP. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 01:14 am: |
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Hello Winfried and Roger,
My YE have PCB "Unit type 408" according to service manual. On the side of cuprum is written "COPAL". On the side of parts is written "48.3". Integrated circiut has cylindric metal case with eight wires. IC is signed "M5126" and "9252" and logo Mitsubishi.
If somebody of you can sell to me this spare part, write direct to my e-mail, please. Thank you very much. |
Roger Provins
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 07, 2005 - 11:00 pm: |
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Sadly the one I have here seems quite different from yours. Much earlier at a guess. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 11, 2005 - 08:43 am: |
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Integrated circuit is maybe different, maybe only different signature. But I think, I can change whole PCB board from other piece of the same model.
What do you think, Winfried ?
I will make picture of my PCB and you can compare they. |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 11, 2005 - 11:50 am: |
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Most ICs (even if they are custom-made, i.e. not available for the public) have two markings: one designator for (manufacturer and) type of circuit, one for the date or batch code. I think the Mxxxx designator (M may stand for Mitsubishi) should be the same on ICs on assemblies of identical design, the second code may vary. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 13, 2005 - 02:26 am: |
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Pictures of PCB in my Yashica are there:
http://muj.proit.cz/roman/ye-pcb/
PCB is released from holders for better visibility.
I will by happy, if somebody can sell my good integrated circuit or whole board from junk camera. |
M Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 16, 2005 - 11:10 pm: |
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Hello. I'm in almost same situation.
After replacing the capacitor on the circuit board, my GSN's shutter still shows doubtful behavior.
Sorry, I have no additional IC chip nor circuit unit to replace with, I'm planning to build compatible unit using discrete devices.
You can access equivalent circuit diagram here.
http://personal.inet.fi/koti/picnet/Y35G/schema3.jpg
(Thank you Mike)
If you prefer I can send you the electrical characteristics of these transistors.
The "2SA156" "2SC182" are Japanese standardized device names.
I will be happy if I can support YASHICA lovers. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 17, 2005 - 02:04 am: |
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Thank you for reply. I have this circuit diagram and I thinking about assembling IC functional equivalent too. But it is not so easy, especially for limited space. I do not have possibility for making miniature SMP board.
I have technical dates of this transistors and I know their equivalent from local available types. It is simple circuit, parameters are not critical.
In my opinion, it is easiest to find damaged or partialy disassembled piece of camera than make new electronics. In Japan absolutely sure. |
Roger Provins
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 17, 2005 - 12:01 pm: |
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Roman,
The board I have appears to be the same as the one in your photos but it is filled with quite different electronics. You are very welcome to it if it will be of any use to you. Please let me have an address privately to [email protected]. There are some Yashica schematics on my web pages http://www.provins.org.uk |
M Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 18, 2005 - 03:44 am: |
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Roman;
Yes, You are right. It's easier to find another camera for parts.
I always would like to rescue YASHICA as many as possible.
Assuming that I have two malfunctioned YASHICAs.
Possible results:
two non-working YAHICAs ----- worst
one working YASHICA and one YASHICA for parts ----- very good job!
two working YAHICA ----- best
I often begin struggling with junk camera even if it is sold "for parts". :-) |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 18, 2005 - 07:56 am: |
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Hello Mr. Yonezawa, Roger, Winfried and all,
During my looking for spare parts I got to know than relative lot of Yasicas with defect electronics are there. So I joined with some other Czech Yashica's fans and we will try to make new electronics board for Yashica Electro, from modern parts, maybe on SMT technology. Two of us are electronics developers. If it will by successful, we can offer new electronics to Yashica's fans and collectors worldwide.
Anybody who can join to us, maybe only for information, please write to me to e-mail [email protected] |
M Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 18, 2005 - 08:21 am: |
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It's very interesting!
I will join you. |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 22, 2005 - 01:12 pm: |
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To change the subject, I bought a GS for a fiver,recently. Looks like new. Meter works, except for test light. The problem is that the focus ring wont turn,and the wind lever is stuck. The aperture ring turns. I looked under the top and it looked OK. There is one screw on the base that wont move and I don't want to chew it up. Any suggestions, anyone? |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 23, 2005 - 08:52 am: |
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Battery test is different circuit, independent on exposure automatic circuit. Might be only bad lightbulb. PCB of battery test circuit is located under bottom cover.
For frozen screw. First try WD-40 liquid. If it not help, insert srewdriver into screw slot and rap by small hammer on srewdriver gently axially, and try release screw. You can repeat it several times. |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 23, 2005 - 12:39 pm: |
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Thanks, Roman, I'll try the WD soak. Then the problem will be to find what's making the focus ring stick, also the wind lever. Could the two things be connected? Cyril. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 23, 2005 - 01:19 pm: |
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IMHO not movable focus ring and wind lever are two independent defects. Focusing mechanism isn't mechanically connected to winding mechanism. I'm very sorry, I can't help you more remote. I will have to see your camera for finding what is wrong. Where do you live? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 24, 2005 - 03:58 am: |
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I just reassembled a E35 and found that sometimes the focus ring was very stiff. Loosening the set screws around it and tightening them with more or less equal torque helped a lot. The gap between the focus ring and some other parts of the lens barrel seems to be very small, so de-centering of the focus ring by tightening the set screws makes it stiff. |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 24, 2005 - 12:38 pm: |
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Roman,I live in Lancashire, England; maybe a long way from you, so seeing that the camera didn't cost much I'll try fiddling with it carefully. Winfried, the set-screws were a bit loose and I tightened them.How do they engage with the focus barrel? Do they slide in a helical groove? |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 24, 2005 - 01:24 pm: |
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I think they slide in a v-shaped circular groove. I am not sure what makes the focus ring bind when the set screws are tightened in the wrong order but obviously they have to be tightened evenly. You should try to loosen one of the set screws a bit (max. 1 turn) and tighten the more or less opposite one. |
Ernesto J. L´Episcopo
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 25, 2005 - 10:21 am: |
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Hi Guys!
Reading the post of the unknown IC, I would say that all analog automatic exposure systems are based on a constant current which charges a capacitor which later determines opening time of the shutter. This M5126 could be a comparator, an Operational amp (either used as comparator or Constant current supply). 9252 stands for year 1992 and production week 52.It is unlikely a custom device as long as production rates in Japan (or any other country/maker)for ANY IC should be of millions instead of thousands of units. Most makers adopt an unusual numbering scheme for "special" or "custom" products, which in fact are just normal products. Then, checking connections to the other components (capacitors, resistors, potmeters) may show which kind of IC is it, and checking against data sheets, which other IC can be used as replacement part. If you Roman have enough time to check connections, and send the drawings/schematics you get, I would (if possible) give you some clue about the possible replacement, but I won´t give any warranty of suitability. You must check it with the help of an electronics technician. Best regards to all of you! |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 26, 2005 - 05:37 am: |
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You are at least partially right. I have a Agfa Selectronic (rangefinder) which has a shutter with similar features to that of the E35. It uses a standard comparator circuit (which probably once was available to the public) to drive the shutter solenoid. I could find a basic description and pin layout in an old databook.
However, I think the circuitry of the E35 is somewhat more complex (the Agfa Selectronic has no indicator bulbs) and therefore there won't be a direct off-the shelf replacement for the IC. Remember that those cameras had production runs of several 100,000 to millions. Any IC manufacturer will be happy to make an IC to order, or to modify an existing design if you buy 100,000+.
BTW I once found two analog switch ICs inside a german Grundig tv (for channel selection). They were made by Texas Instruments and had a standard SNxxxx device number. At that time I was working for a major TI distributor in Germany and had close contact to their sales people and their Munich IC fab (which made some analog IC designs). Even those people could not supply a replacement, obviously this IC was sold to Grundig exclusively. |
M.Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 26, 2005 - 07:23 am: |
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Hello Cyril;
The winding mechanism may be locked at "charged" position.
You can see a small lever under the top cover.
See photo at:
http://album.nikon-image.com/nk/NImageAlbum.asp?key=243.197841&src=5559477&un=67169&m=0&pos0=1
The lever should go down to reset the locking cam when you press the shutter button.
M.Yonezawa |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 26, 2005 - 12:37 pm: |
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Hello Ernesto,
IMHO IC in later models of YE35 is "customer circuit". It have very simply structure which consists only four transistors, four resistors and one termistor. Maybe it is hybrid IC. I'm sure it is not operational amplifier nor comparator. IC circuit diagram very probably copied exactly older version assembled from discrete components. You can see to schematic on Roger Provins pages http://www.provins.org.uk |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 26, 2005 - 02:46 pm: |
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Thank you for the info. and the photo, M. Yonezawa. At least I can get the top off, which gives me some encouragement. The screw and the focussing are still stubborn, though. Cyril. |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 27, 2005 - 02:25 pm: |
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Hello M.I followed your instructions using the very clear photo and probed the cam, and lo and behold, the wind lever now works normally. The counter also revolves OK. But-on pressing the release button there is only a single click and the shutter doesn't fire. On my GTN there is a rapid double click.( The focus is still frozen, as is the screw on the bottom. I have also had no success removing the lens name-plate. Will have another go later.)Cyril. |
M.Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 28, 2005 - 09:25 am: |
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Hello Cyril;
For the focus problem, it may be better to check the movement of the range finder arm.
Or something around lens barrel arm may locks it.
http://album.nikon-image.com/nk/NImageAlbum.asp?pos=5&key=243.197841&un=67169&m=0&pos0=1&cnt=1526
http://album.nikon-image.com/nk/NImageAlbum.asp?pos=4&key=243.197841&un=67169&m=0&pos0=1&cnt=1449
M.Yonezawa |
Cyril Lowe
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 28, 2005 - 01:03 pm: |
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Thanks M. I checked the things shown on your pictures. There's nothing to be seen in the gap, the rangefinder arm moves when pushed with a screwdriver,but the lens barrel arm is solid. I think this means that I will have to go into the barrel from the front. The lights don't come on now, and the wire has detached from the PC terminal. There's no end to it! Hey-ho! Cyril |
M.Yonezawa
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 01, 2005 - 08:22 am: |
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Hello Cyril;
Yes! We are now going long and winding road.
You can de-assemble lens barrel to access helicoid and shutter unit.
See:
http://album.nikon-image.com/nk/NImageAlbum.asp?key=243.197841&src=5597681&un=67169&m=0&pos0=1
But it's worth try to apply some alcohol
or lighter fluid to helicoid slit.
Refer to:
https://kyp.hauslendale.com/classics/forum/messages/674/2183.html?
We have NO TIME LIMIT for our hobby. :-) |
Carlos Garcia
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 25, 2005 - 11:05 am: |
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Hi guys;
I have a problem with my Yashica electro 35 GSN, indicator lights works properly and accurate (both of them), battery test works fine too, but the camera only shots at 1/500 as NO BATTERY, also in "B", I have replaced the pad, check for any wire lose, etc, all looks fine... any idea?. I am in Lima Peru (south america) nobody here wants/knows how to repair it
Thanks
Carlos
P.S.- please.... HELP!!!! |
NICHOLAS MUTHEE MUITA
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 02, 2005 - 07:42 am: |
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HI I HAVE A PROBLEM WITH MY COPAL MINILAB ML 7050 .THE IC50,IC51,IC52 OF THE MACHINE PART PA5-50550.2 08A-MCP PCB .I NEED TO REPLACE THEM CAN SOMEONE GIVE A SALE OFFER URGENTLY. |
Roman Dubravsky
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 02, 2005 - 03:57 pm: |
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Hello Carlos Garcia,
It looks as bad electromagnet. Check circuit between two black wires. |
