Archived posting to the Leica Users Group, 1997/07/03
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi, I've purchased the MR-9 adapters for My Canon F1's and Pentax Spotmeter. I still have some new PX-625 cells (from Europe) but can no longer find the 640 cell the Spotmeter uses. I bought the adapters so that I could evaluate them while I still had the real thing on hand as a comparison. The adapter uses a shottky diode as a voltage dropping device, there is no voltage regulation. The voltage drop is approximately .2 VDC, therefore if the voltage on a new silver cell is 1.6 volts the output voltage will be 1.4 volts. I have cross checked my cameras with both the MR-9 adapter and a real PX-625 battery and have found the difference in the meter readout to be nominal, i.e. less than 1/4 stop. I call this nominal as I often see this difference between camera bodies. If the camera being used had an internal voltage regulator there would be no issue here. Neither the F1's nor the Spotmeter have any sort of regulation so in use I would expect a slight change in operation as the cells voltage drops. One solution proposed on the Canon FD mailing list was to bleed off the voltage through a 10K resistor until the voltage on the silver cell drops to 1.55 V. I have not tried this personally but the feedback on the FD list indicates that this works well. The adapter is not a perfect solution and I will continue to scrounge for new Mercury batteries, but based on my tests I would not hesitate to rely on the MR-9 adapter when my supply of PX-625's run out. Kent Smith unipac@teleport.com - ----------- Carsten Bockermann wrote: >>C.R.I.S. Camera Service (who does Canon F-1 repairs by the way) >>developed a product called the MR-9 Adapter Has anyone here tried the MR-) adapter and can provide us with some information based on his experience ? Carsten - ----------