Honeywell Pentax ESII needle drop is kicking my butt

[Bill Burk]

I’m doing CLA on an ESII following repair and parts manuals from learncamerarepair. Great site, by the way.

D (black), is supposed to be infinity to ground+ when circuit board is out and SMCT lens is at f/8.

But it’s short to ground. I’ll try to figure out why.

 

[gone]

I see at least 2 black wires. Something I learned the hard way w/ auto wiring diagram schematics is that the wire colors are not always a match w/ the product. At some point the multi-meter needs to come out to see what is really going on. With DC, red is normally hot and black is ground, but I wouldn't accept that as the gospel, it sometimes isn't that simple.

 

[Bill Burk]

Ready for that. The wires are pretty, about a dozen different colors. Black is used for battery minus (body ground is plus).

To check when I get home. Is it infinity to body ground+ because it is battery minus?

 

[ic-racer]

Is the meter shot? Or are you just verifying the test points?

 

[Bill Burk]

Is the meter shot? Or are you just verifying the test points?

The camera is misbehaving. I am sure there is a fully functioning camera in there somewhere.

Meanwhile it “acts” all the time like I put a Super Takumar on it and forgot to push up the stop-down switch.

Test points are supposed to be read with batteries out.

Now I am chasing other wrong ohmmeter readings.

I know the CdS cells are good. I know the main circuit board is good.

 

[ic-racer]

Try reflowing solder joints. This blind approach has solved many problems for me. Like this one:

Rollei Metz SCA 356 Adapter Repair

I got a Metz 54MZ-4 to use with a SCA 3562 adapter and Hy6. I thought it would be nice to use the flash on older Rolleiflex equipment with the SCA 356 adapter. I found one 'new in box.' Turns out it works but some of the functionality did not work all the time. The little lightning bolt...

www.photrio.com

 

[mshchem]

I had a ES back in the day, bought it new, it was a great camera. Working ones seem rare on Ebay. Good luck these are neat cameras.

 

[Bill Burk]

Looks like I spotted the point that was broken. I touched two points on the CdS circuit board and they respond to light. Then I touched one point on the board and one on ground and the multimeter did not respond to light.

Then I touched the place where body and board meet and it moved!

Soldered it, now speeds all over 1000 but my guess is previous repair failed to diagnose, adjusted it like nuts and gave up.

Will swap in my circuit board to see if speeds fall in range before going further. But this broken junction might have been it.

 

[ic-racer]

Great find Bill!

 

[Bill Burk]

Well maybe not. The CdS cells don’t have the full range they need. Back to looking for parts.

 

[flavio81]

learncamerarepair

Nice to see you here dear comrade!

Well maybe not. The CdS cells don’t have the full range they need. Back to looking for parts.

Why not recalibrate the board? I would be very suspicious of blaming the cells themselves. The ESII is a later Pentax, i don't think the cells would really suffer any degradation. So far, the only times i've found bad CdS cells was on an old (early-60s, Photomic TN model) Nikon F, and on a first-gen Spotmatic. Then many other equipment often has its cells just fine, even 60s equipment. For example i have a Gossen Luna Pro that works perfectly, completely calibrated. 70s equipment, i haven't found worn CdS cells so far.

BTW, did you try resoldering all solder joints on the main board and around the cds cells too? Are the contacts for the main board (and the socket connector) clean?

My philosophy is to clean all switches and contacts before moving any potentiometer or replacing anything. And the cold solder joints, i raise it because the ESII boards' traces aren't protected with any kind of environmental coating (unlike later pro electronic cameras).

 

[flavio81]

I’m doing CLA on an ESII

BTW, i have something for you. The adjustment procedure for the ESII. It is hard to find because it is within a SPF service manual or supplement. I'm attaching it here. Page 6 of the PDF, and following pages, cover the ESII.

Also download, from the learncamerarepair website, the ES service manual, it also details the calibration steps. But this PDF helps to locate the actual potentiometers on the ESII board.

 

[Bill Burk]

Thanks @flavio81 ,

I’ll always wonder where the two ‘never should be adjusted’ potentiometers were supposed to be. Should have taken a picture of the board.

CdS were indeed bad, metering 6 and 10 ohms in the dark. Lucky for me I bought a bag of assorted CdS from Radio Shack before they went under.

I have replaced them and initial test shows I can get full range of shutter speeds by dialing the light up and down. So it will calibrate! I made a rookie mistake routing the leads, I should have gone to the notch. The insulation will be against the upper case pressing against a lead. I don’t like it but it will close.

I left the seal replacement work to the end so there is that work ahead of me.

But to sum it up. The connector to the CdS was broken, the mirror return was stuck, the shutter switch was cracked, and the CdS were bad.

Otherwise the camera was in very nice condition.

 

[Bill Burk]

Ack it’s not calibrating. I can get the meter to show the right speeds across the scale but then the shutter actual shutter slow speeds go down like a rock

 

[flavio81]

Ack it’s not calibrating. I can get the meter to show the right speeds across the scale but then the shutter actual shutter slow speeds go down like a rock

Hmmmm

For the auto shutter to work ok, many things need to be right, i.e. the timing switches/memory switch needs to be clean, memory capacitor OK (i think it's inside a sealed compartment on the ESII). Have you checked all switches to be clean and checked their adjustment (i think the manual of the ES describes the adjustment of many of them)?

 

[Bill Burk]

Hi @flavio81 I’m certain the properties of the substitute CdS are wildly different enough from factory CdS that the few ohms adjustments available on board are not enough.

Considering dropping in a few variable resistors of my own.

That pdf you sent is great.

My board is Type II pg10 and range of the first one “auto speed EV12” can’t get down to 60. It gets about 1/15. So I might add a resistor next to it or change out that one.

Also struggling with the value proposition. A serviced and working ESII is on eBay for the price I paid for this parts one. So I won’t be creating much value fixing these things.

 

[flavio81]

Hi @flavio81 I’m certain the properties of the substitute CdS are wildly different enough from factory CdS that the few ohms adjustments available on board are not enough.

Considering dropping in a few variable resistors of my own.

That pdf you sent is great.

My board is Type II pg10 and range of the first one “auto speed EV12” can’t get down to 60. It gets about 1/15. So I might add a resistor next to it or change out that one.

Also struggling with the value proposition. A serviced and working ESII is on eBay for the price I paid for this parts one. So I won’t be creating much value fixing these things.

Try sourcing the CdS cells from a Spotmatic F or K1000.

 

[Bill Burk]

Well I picked up another ESII, has a different ( type III ) board. Also same issue with CdS cells (about 4K ohms with little response to light).

These Japanese 20 dollar ESII must come from the factory returns bin.

I’ll keep an eye out for Spotmatic F’s

 

[Bill Burk]

The first ESII is still kicking my butt.

Sure learned a lot.

I have put 0.6 ND filters over the cells which are larger than original so they were too sensitive.

The gates of my frequency counter are getting harder to adjust, so I can’t trust it to count time.

I adjust for 1/60 as follows: First I tried by sound, listening to hesitation in the second curtain. It wasn’t accurate enough.

But then I got an idea: How about watching for the second curtain incursion into the film gate with flash? It’s great! I adjust until the whole gate is illuminated by flash.

For 1/1000 I marked the point where incursion of the second curtain with flash is same as manual 1/1000.

Still had to tweak a resistor on the board until I could get 60 at EI 100 f/8 and EV 12, while getting 1/1000 at EV 16.

Getting all this together and then EV 8 gives me more than 8 seconds…. Such a fight..

All because the CdS were bad and I tried replacing yhem with what I had on hand.

 

[Bill Burk]

The second ESII I am repairing has a “bad” prism and eyepiece lens. The mirror box wiggles and I don’t know how to fix that. But it’s got good CdS cells and seems like these electronics will calibrate! I may do the old switcheroo.

 

[Kodachromeguy]

Are failing cds cells a common or typical failure point for these ESII cameras? I wish I had bought one years ago.

 

[Bill Burk]

Are failing cds cells a common or typical failure point for these ESII cameras? I wish I had bought one years ago.

Haaa. I don’t think so. My old ESII is fine, the one I bought second hand in 1980 from Olympic Camera in LA when I got my first job out of school.

I think overall the CdS failure is rare. But I think the current stock of bodies are factory returns which were held because they could not calibrate.

My second one calibrated!

The trick is to clean the contacts. When I was getting unreliable speeds I found two places where contact was inefficient. The eyepiece (CdS to ground) was finger tight. That was my fault. The next place I cleaned was the lower body capacitor section.

At first I suspected bad capacitor and started to remove the unit. Then, seeing it was sealed, I put it back. But I cleaned the contact under one of the screws, and cleaned the screw itself.

I think cleaning contact points is pretty important.

 

[Bill Burk]

Status update: I now have four ESII- the original I haven’t touched that I bought in the ‘80s, the two I have been talking about, and I just got another to keep the ball rolling.

It’s more and more apparent to me that these ones on the market are Honeywell/Asahi factory warranty exchanges.

I have one of these up completely calibrated with film in it that I will be doing a deviation check by sensitometry. But while showing it off over the holiday weekend I found occasional misfires. Like I would want to demonstrate the locking shutter on 8 second exposures and it gave a sixtieth. But I think my good one is mostly good except misfires.

The “bad” one (with bad CdS that I replaced with Radio Shack CdS and added “extra” trim resistors because their properties are far different from factory CdS) was close to calibrated (slow speeds dropped too fast below EV8).
But after sitting a week the bad one has developed a problem. It no longer delivers speeds above 1/60. I test by using flash and watching the curtain shadow infringe the gate as I crank the light above EV12. I know it worked last week. But now, although it will go slower, that second curtain just never infringes the gate.

Now the new one has good prism, good CdS cells (meter responds close to calibration across range), but its electric shutter isn’t kicking at all.

I know what I can do here, take the good CdS, prism and board over to the one that calibrated last week.

But I wonder why suddenly the “bad” one won’t infringe the gate over 60. And I don’t exactly know how to solve the new one’s “no electric shutter” issue.

p.s. Shutter release travel is very long on the new one. I have to press hard after pressing all the way down to fire.

 

[Bill Burk]

Ack this happened before. Soon as I take off the top, the “bad one” works. I’ll be looking for a short somewhere between the upper deck and the top. Maybe I will address the low light non-linearity.

 

[Bill Burk]

As mentioned the issue was reproducible, it followed putting the top on, and went away with the top off. Solder connection on the right. I loosened the two silver screws and twisted the circuit board clockwise to move that solder away from where it probably touched. Filed the edge because solder went to the edge of the board. Problem positively went away.