Author Topic: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!  (Read 1189 times)

richardHaw

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Re: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!
« Reply #15 on: December 25, 2018, 10:17:44 »
Glad to be of assistance.
I just took a look on eBay and was shocked that FM3a prices are so high: US$750-1000.
The FM3a feels so solid but light. And compared to my Df it is positively tiny.

they are the most expensive. they say that not many were made because the FM came out soon after  :o :o :o

richardHaw

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Re: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!
« Reply #16 on: December 29, 2018, 03:40:14 »
https://richardhaw.com/2018/12/29/repair-nikkormat-ftn-part-2/

here's part 2!

I will post the diode article on part 3!  :o :o :o

the bottom is too cramped. let's see if I can fit a diode there  ::)

Akira

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Re: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!
« Reply #17 on: December 29, 2018, 04:40:48 »
they are the most expensive. they say that not many were made because the FM came out soon after  :o :o :o

You mean, FT3?  Lorne meant FM3a with the electric-mechanical hybrid shutter.
"The eye is blind if the mind is absent." - Confucius

"Limitation is inspiration." - Akira

richardHaw

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Re: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!
« Reply #18 on: December 29, 2018, 04:43:12 »
You mean, FT3?  Lorne meant FM3a with the electric-mechanical hybrid shutter.
yes FT3  :o :o :o

Hugh_3170

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Re: Nikkormat FTN, Nikon FE and Nikon FM2n repair articles!
« Reply #19 on: January 06, 2019, 07:44:13 »
This approach using a Toshiba IC regulator chip is food for thought:  http://www.robotroom.com/Mercury-Battery-Replacement-Regulator-1.html     

The forward voltage drop of a 1N5711 Schottky diode, for example, is quite dependent on the current draw, which for the Nikkormat varies between ~ 0.03mA in dull light (EV3) and up to ~9mA in bright light (EV17), which means that in dull light the voltage drop across the Schottky is too little and in bright light it is too much.

Spec sheet for the IN5711: https://docs-apac.rs-online.com/webdocs/0da3/0900766b80da3e34.pdf 

The Toshiba IC regulator chip is very small and controls the output voltage within tight limits over this range of currents.

On the other hand, if the galvanometer balance current can be reset for the higher currents created by the 1.55volt Silver cell, then that would be the simplest solution I am now thinking.


i bought a batch of 1N5711  :o :o :o
Hugh Gunn