searching for info about Pentax spotmeter V

[Christophe1]

My phone camera completely over exaggerates the light that the bulb provides. The light is barely visible when it’s working properly and it only lights a few numbers so you can see the needle when the light you are measuring only registers 1 or 2

Hi Bill, thank you for the remark and the picture. Yes, it is probably very dim. I heard that from other people too, But the fact is that I've tested the light bulb outside the circuit and it still is going strong up to 4.5 V. And I have no idea why it should be so faint in the meter. I can only think of one explanation, namely that it perhaps influences the light metering itself, because it is placed in the casing where the mirror sits. And I'm also wondering, if I bypass the circuit with wires coming directly coming from the contact (well at least for the positive side) if this would change something in the circuit, because maybe the lamp is only an isolated subcircuit; or so I guess from what I derive from the repair manual from the older model 1/21. But I'm far from an expert in electronics so I could be completely wrong.

 

[Christophe1]

Honeywell, was the US distributor, and had Pentax label some of the equipment sold in the USA market as "Honeywell". I understand this was intended to block US residents from Importing Pentax Equipment from other countries. (basically the nice customs folks were told that Honeywell Pentax was a Honeywell Trademark and they should block importation of anything that said ASAHI Pentax as being a fake)

Ok, I see. Then the design was Pentax.

 

[MattKing]

Ok, I see. Then the design was Pentax.

The meter itself was designed and manufactured by Asahi Pentax, and known as Asahi Pentax in most of the world.
The brand name varied in the USA because of the distributor/importer's decision.
Similar to Bogen (really Manfrotto) tripods.

 

[Christophe1]

Your eye needs to be adapted to the dark to see it.

Ok. It remains strange in my opinion. I'm also wondering if this could have been a design error, because it seems that there is no distinction between the place of the light bulb in the 1/21 and the V. But they have different voltage. Lamp voltage in The 1/21 is only 1.3v but in the spotmeterV it is 4.5v. So with the same light bulb of let say 6 V it would make a huge difference, although it would be brighter in the spotmeterV. But in the case of a 1.5V lamp it would be different, and a resistor would be needed in the latter.

 

[Christophe1]

The meter itself was designed and manufactured by Asahi Pentax, and known as Asahi Pentax in most of the world.
The brand name varied in the USA because of the distributor/importer's decision.
Similar to Bogen (really Manfrotto) tripods.

I see.

 

[Christophe1]

Ok. It remains strange in my opinion. I'm also wondering if this could have been a design error, because it seems that there is no distinction between the place of the light bulb in the 1/21 and the V. But they have different voltage. Lamp voltage in The 1/21 is only 1.3v but in the spotmeterV it is 4.5v. So with the same light bulb of let say 6 V it would make a huge difference, although it would be brighter in the spotmeterV. But in the case of a 1.5V lamp it would be different, and a resistor would be needed in the latter.

But only a repair manual or someone with experience in repairing these meters could explain all this I guess. Too bad for me that the latter are mainly in the US, rather expensive for me to send it from Belgium, and then it is not even repaired. For all the costs I could buy a new one. Not that I want to be condescending by the way about the people who repair, it is just a objective reflection.

 

[AgX]

The meter itself was designed and manufactured by Asahi Pentax, and known as Asahi Pentax in most of the world.
The brand name varied in the USA because of the distributor/importer's decision.
Similar to Bogen (really Manfrotto) tripods.

Next to this we have cases where the original manufacturer is still labelled, but the product itself got a new designation, as with Berkey the US-importer of Gossen meters.

 

[AgX]

This scale illumination one has to put into perspective. None of my meters got an illumination. And in case one would need such, the same time there would be the need to illuminate the scales at the lens or camera. Thus some light that does not disturb ones vision would be handy anway.

 

[Bill Burk]

It may be dim to avoid impacting the reading.

But right away you can tell what’s going on. The light is only as bright as it needs to be. It’s an engineering decision. The only time you can’t see the needle is when it is so dark that you can barely get a reading at all. Hence that’s the only time you need it. When you do need it, it will be just enough.

When “playing” with the meter to see if all the buttons are working, you will likely be in a brighter space, so it will “seem” like the bulb isn’t working. The engineers didn’t think of that scenario at all!

 

[Christophe1]

Welkom bjj Apug!

https://fdocuments.in/document/pentax-spotmeter-1-21-repair-manual.html

There are pages missing by the way in this version.
See https://www.sekaimon.com/itemdetail.../21º+Spot+Meter+Parts+List+for+Repair+Reprint
On the bottom of the page it is stated (in English): 12 pages. If you look at the numbers you see in the online version, there are all numbered, front page is 1, but it doesn't reach 12.
The listing of electronic components is clearly absent.

 

[AgX]

Your link is dead.

 

[Christophe1]

try this one
https://www.ebay.com/itm/313681435798

 

[AgX]

The pdf I linked to contains pages 1-10 + 5a (with a different circuit)
It contains a parts list and all the 3 pages on Ebay. It even is more up to date than the Ebay version as it in addition contains the 2nd version of figure 4, the new circuit, on page 5a.

 

[Christophe1]

The pdf I linked to contains pages 1-10 + 5a (with a different circuit)
It contains a parts list and all the 3 pages on Ebay. It even is more up to date than the Ebay version as it in addition contains the 2nd version of figure 4, the new circuit, on page 5a.

Do you have the Ebay version?

 

[AgX]

No, but at the moment we can talk only about we got accessible. And I would not know what is missing in that pdf.
Parts/assemblies listing goes to #115, which is all there is installed. Are you missing a page on calibration? You would not find such in a parts list.

 

[Christophe1]

No, but at the moment we can talk only about we got accessible. And I would not know what is missing in that pdf.
Parts/assemblies listing goes to #115, which is all there is installed. Are you missing a page on calibration? You would not find such in a parts list.

Ok, I see. Wrong speculation from my part.