Honeywell Pentax 1°/21° Spot Meter - repair help

[chase canadé]

Hi -
I'm hopeing someone here at LFPF can help me out with a copy of a service manual or Parts list with exploded views or both for a Honeywell Pentax 1°/21° Spot Meter.

I want to take it apart for what i hope is a simple repair and cleaning. The previous owner must have left the batteries in and some slight corrosion accured. I believe i can fix the meter - i think it is either a contact or bad wire. The most corrosion was in the "L" side battery compartment which i've cleaned the contacts and got the latch to work smooth again. I think the corrosion may have traveled the wires and is causing some issues; or it's both the On switch and wires. High side seems to be working fine.

As i'm sure some can relate, I prefer to do the repair with a exploded view of the parts or repair/service manual in front of me. So if you have this and can send a PDF of it or pretty clear JPG to get me through this - it'd be appriciated.

I have searched the net and so far aside from sellers or the owners manual found nothing. This is a DIY repair and i know many of you from reading the forums also do DIY repairs to gear - so i'm hoping this will not be a hard find and someone would be kind enough to send it as mentioned.


here's a pic of the type it is...
http://static.photo.net/attachments/bboard/00U/00UtWd-185731584.jpg

(Notice it is Pentax 1°/21° Spot Meter with-out the side light switch)

PM me here if you can help and i'll send my email address
or post a link for download if you know of a link the net and i missed it in my searches; or your hosting a copy temparaily.

tia
chase

[Wally]

I've got this exact same model. I bought the tech manual for it, but it didn't include calibration, and I have no good idea where I hid it. But here's some clues.

Disassembly is a _bit_ tricky. There's a little screw under the small glued-on metal plate on the side near the battery compartment. Also unscrew the eyepiece.

The corrosion is most sensitive where the copper plate under the battery lid gets oxidised - this is the path for current for the small battery, and even small bits of corrosion will make the meter fluctuate, so clean these components until they're shiny.

The schematic is easily traced out.

This unit when made was calibrated against a mercury battery, not an Alkaline (the little button battery that's used in normal light). There are two disadvantages to using an Alkaline - it's not the same voltage as a Mercury battery, and it's discharge curve itn't nearly as flat as a Mercury battery. So you'll have to calibrate it's trimmers for a new Alkaline, and watch the battery's age closely (the button cell). The 9V battery is switched in when you press the "low light" button, and any regular 9V Alkaline should be fine.

Good luck, these are still great meters, and very easy to visualize zones on the dial.

[RichardRitter]

Pentax stop making this meter around 1980. No parts are available for it. As the photo cell ages it become more red sensitive.

[Joseph O'Neil]

Pentax stop making this meter around 1980. No parts are available for it. As the photo cell ages it become more red sensitive.

Okay, a really *stupid* question here. I just picked up one of these light meters from an auction, and it works fine, although mine is the Asahi (spelling?) Pentax, but otherwise same vintage. I also have two newer models, also both analog. (Yeah, I guess you can say I like these meters. :) ).

But back to the dumb question - if they become more red sensitive with age, how does that affect, if at all, metering for red sensitive film? For example, I still have a fridge full of 4x5 tech pan, and a couple boxes of near IR film (Maco I think) too.

does the older meter work better or worse for that kind of film? :confused:

joe

[RichardRitter]

When Pentax took over this style of meter they made it with a single scale and the body of the meter is gray and the photo cell is silicon diode.

As to the amount the older ones with the CDS cells change is not known and probably varies from meter to meter.

[chase canadé]

Hey Wally thanks for the discription of dis-assembly - you mention a small screw under the glued on plate near the battery compartment - i take it this is the small silver oval seen in the above picture towards the battery compartment... correct?

I take it also the 4 screws on the bottom (open battery compartment) have to come out as well... correct?

What about the scale on the side? Does this have to come off first before the two halves of the handle /body can be taken apart? And does this require a special tool to unscrew - looks like a double pin thing ( don't remember the name of the tool) for the screw - (seen in the pic as well - center of the scales)


Richard - well - that doesn't sound good... as a matter of fact that sounds bad. Is there a way to test the sensitivity? before dis-assembly in this case.

That news really makes me go - DANG!... i heard so much good about these meters too. and i finally got one... thought it might be a simple fix and i'd have a kick butt meter finally!

Is it possible it didn't get more red sensitive? lol

What about the Pentax V? suceptable to sensitivity changes for red?

Hmmm and my Mamiya chimney has a cds meter too - Would that be effected by age the same as the Pentax as well?

[chase canadé]

One other question i had conserning this meter maybe one of you can answer. More curiosity than anything

I just noticed something - the Manuals suggest this is looks more like the Asashi Pentax spot meter II which is a 3/21 degree meter

Mine says Honeywell of course and 1/21 degree meter - yet all the manuals i find for the Honeywell 1/21 spot meter show it should have the light button on the side.

I take it the label on the meter is not incorrect - so is this one the first after Honeywell put their name on it?

I wouldn't ask if i could find the correct user manual for this model.

and one last one for Richard - I notice you repair these type meters - with what you say of the cds cell - is this worth bothering with - repairing i mean? Or any of the Pentax Meters for that matter with a cds cell.

If they are not going to accurate because of the cds degridation and it reads high in the red zones, i would think it's usless for photography - and since there are no parts as you say - would you say it''s pretty much useless all together - and this would hold true for all of the Pentax's up to the V correct?

[RichardRitter]

Honeywell made the meters first label Honeywell, then they were labeled Asashi Pentax still the brown body with two scales. In the early 80 when Pentax came out with the digital meter they change the style you have to the Pentax V with a silicon cell and a single scale.

The meters works and give fairly good reading you should be aware that early morning and late afternoon light may read more of the red in the light then the film is seeing and will tend to give an over exposure in those type of light.

Now here is the instructing part, silicon cells are also fooled by the same type of light.