[tonyzoc]

I picked up a Spotmatic F off eBay as "used" and of course there were many problems but with a little cleaning and lube it working fine, except for the flash...both the hot shoe and the PC socket. I changed the camera top with a cleaner SPF I had and that didn't fix it. Also I cleaned the hot shoe contacts inside and outside. I don't know how the flash is triggered or if the pc socket is in series with the hotshot or wired separately. I suspect the issue is at the source of the flash. I looked in the base but didn't see anything resembling flash contacts. Any ideas?

[AstroDave]

I changed the camera top with a cleaner SPF I had and that didn't fix it

I'm no Spotmatic expert, but ... Is the hot shoe not attached to/part of the top? In which case, there should be some kind of wire from the body to the hot shoe that you would have had to dislodge/remove.

or if the pc socket is in series with the hotshot

Seems VERY unlikely they are in series - you would need something (flash + ??) attached to both in order for the flash to work - no matter to which it! was connected! Parallel perhaps.

[tonyzoc]

I'm no Spotmatic expert, but ... Is the hot shoe not attached to/part of the top? In which case, there should be some kind of wire from the body to the hot shoe that you would have had to dislodge/remove.



Seems VERY unlikely they are in series - you would need something (flash + ??) attached to both in order for the flash to work - no matter to which it! was connected! Parallel perhaps.

Yes, that's right...they can't be in series. I checked under the top plate and the pins on the top plate were good, and the body contact was cleaned. Since both hotshoe and PC socket don't work, it has to be the trigger on the first curtain opening... But I don't see any contact so it's probably under the mirror box somewhere. Probably something I'm not going to try fixing....though I do have a parts body I could play with to see where the trigger is.



---------- Post added 04-12-21 at 12:04 PM ----------

Looking at a Spotmatic service manual I see the flash contacts are on the side of the mirror box housing... So I'd have to remove the mirror box. Before I try that I'll see if I can identify the lead coming from the contacts and test that first. My guess is either a broken wire or the sync contacts in the mirror box are dirty or oxidized and need cleaning.

[stevebrot]

I don't know how the flash is triggered or if the pc socket is in series with the hotshot or wired separately.

Yes, that's right...they can't be in series.

The hot shoe is enabled by a small switch under the tension spring to provide partial isolation of the shoe contacts. The X-sync (both shoe and PC) functionality is in series with the FP sync (triggered by mirror going full travel), such that X does not fire if FP has not closed. I have a copy of the wiring schematic, but don't have it in front of me. I believe it is part of the detailed parts list reference.


Steve

[tonyzoc]

The hot shoe is enabled by a small switch under the tension spring to provide partial isolation of the shoe contacts. The X-sync (both shoe and PC) functionality is in series with the FP sync (triggered by mirror going full travel), such that X does not fire if FP has not closed. I have a copy of the wiring schematic, but don't have it in front of me. I believe it is part of the detailed parts list reference.


Steve

Ok...it is in series then...the two pins in the hot shoe tell the camera a flash is mounted(?) so the circuit is closed (bypassed) when no flash is not mounted...and the X and F both close on the mirror up.

So, there could be a problem with the hotshoe, but I switched top plates from a camera body that did fire the flash. So either I got a bad wire or bad oxidation of the X or F contact blades.

[stevebrot]

Ok...it is in series then...the two pins in the hot shoe tell the camera a flash is mounted(?) so the circuit is closed (bypassed) when no flash is not mounted...and the X and F both close on the mirror up.

So, there could be a problem with the hotshoe, but I switched top plates from a camera body that did fire the flash. So either I got a bad wire or bad oxidation of the X or F contact blades.

Hot shoe and X-sync PC are in parallel with each other, but with the hot shoe switched; both are in series with and dependent on the FP (X current is through the FP switch). Below is the general schematic for Spotmatics (lacks hot shoe part)...

General Spotmatic schematic


You might want to check sync for FP first and adjust if needed.


Steve

[tonyzoc]

Hot shoe and X-sync PC are in parallel with each other, but with the hot shoe switched; both are in series with and dependent on the FP (X current is through the FP switch). Below is the general schematic for Spotmatics (lacks hot shoe part)...

General Spotmatic schematic
Attachment 530553

You might want to check sync for FP first and adjust if needed.


Steve

FP isn't working either... I probably have a broken wire. I paid $39 for this SPF, so I'll probably just refoam and replace light seals and sell it at is. The meter works, but it's also over exposing by about 2 stops at the high end just like my other SPF.

[stevebrot]

FP isn't working either... I probably have a broken wire.

The next question is whether the mirror is rising fully, because that is what closes the switch for FP.

(I'm not really that into Spotmatic flash sync except that the circuit for X-sync on my SPII remains closed instead of resetting at end of exposure. I was recently researching that one, but have yet to figure it out.)


Steve

[tonyzoc]

The next question is whether the mirror is rising fully, because that is what closes the switch for FP.

(I'm not really that into Spotmatic flash sync except that the circuit for X-sync on my SPII remains closed instead of resetting at end of exposure. I was recently researching that one, but have yet to figure it out.)


Steve

The mirror is going up fully. I thought of that and tried holding it during exposure then slowly lifting it to see if the flash triggered...and it didn't. I also tried the release flick to lockup the mirror.

[pentaxus]

You have to remove the front panel to get to the switch you are looking for. It is there inside and below the shutter dial. You will be able to see a tiny arm rotate and hit the copper leaf switch when you fire the shutter. Also, if your meter is off in bright light, you adjust it by rotating the variable resistor to the left side of the eyepiece. Try rotating the wiper 3mm counter clockwise and see if that fixes the over exposure. The VR's on either side of the eyepiece are to calibrate full aperture metering. After adjusting there you calibrate stop down metering with the VR on the on the circuit board next to the meter movement.