9000+MD-90+NP-90M question

It might be worth sending Pete Ganzell a P.M .
Just a long shot , but he's done a heck of a lot of tinkering with Sony and Minolta gear .
He mightught have a copy of the service manual .
Sounds more like you've got a bad joint though , have you ran a test meter over the contacts to check continuity ?

Much obliged for the reply.
Sorry for the delay in replying.
I've used my multi meter and I'm getting
16.22v across the terminals on the NP-90M.
I've wired and tabbed up as per the original.
I was quite careful to do that.
My NP-90m forwards the film to whatever setting I
choose to use. Fast or slow. No problem there.
I have a clue why the side button doesn't work yet.
I'll make some adjustments and then let you know what I found
if I'm correct.
Once again - thanks for the input.
Robert

Hi,
Just to follow up my previous posts.
The side button on my NP-90M didn't work because I had misplaced the 6 pin
connections on it's face. They are supposed to be positioned sitting on top of the divider steel plate not under it. In other words I'd positioned the pins too low the first time round. Once they were at the right height then a proper connection was made.
My NP-90M works fine now when connected to the winder MD-90.

Changing the batteries on a NP-90M is no easy task. It's certainly do-able
but not for the faint hearted. You have to be able to use a soldering iron carefully and ideally you'd need a mini spot welder as well.You'd have to photograph the wiring once you'd opened the unit. You need precision screwdrivers to do that and the tiny screws are different lengths so you'd have to log that carefully.
The batteries I use are now NimH not Nicad. They are the same size as the originals and took me a while to source from the Component Shop in the UK- at £1 each.
I'm an amateur and for me it was a learning experience. I like to make old things work again.
I know we've all gone digital but my Minolta 9000 still looks good and works fine. It's a well built workhorse.
Probably last me out!

How are you charging them?
If it's a generic battery charger, fast charging in a couple of hours is usually best provided the charger has a decent cut-off. Slow charging Nickel-based batteries ruins them eventually. So does leaving them charged for long periods - which is why non-lithium cordless phone batteries die after a year.

My advice? Keep two sets. Leave one near-flat (10% charge or less) and fast-charge it before fitting into the device. Make sure you swap batteries every month and run the used ones flat, then charge them for a few minutes only and leave them. Don;t leave any batteries except Lithium in devices for more than a month, and even Lithium should be taken out of the device if you don't use it for a month, or they can die too.

1.0 or 1.1V/cell is fine for discharge. Use a low discharge rate if you can adjust this (0.1A), but 200mA or 400mA for charge.

If you ever find your battery won't make the right voltage on charging, but is (say) 1.2V less, then this can be due to an internal short in one cell due to crystallisation. you can correct this by discharging the pack gently then charging at the highest current you can get to get it hot, which melts the crystals and reforms the cell. But don't do that unless you need to!

NiMH seem better than nicads at low current discharge (and usually have higher capacity too) but sometimes not as good at high discharge rates due to the higher internal resistance.

Ah yes, Nailsworth. Driven through it many times. The longest village/town name in the area with no repeated letters. Beloved of a certain kind of navigational clue-writer!

NiMH cells frequently give a higher charge end-point voltage than Nicads (1.4V+ per cell instead of 1.3V+ after fast charging) so if you ever get an error with freshly charged cells, leave them for an hour or two and they may be okay.

Hello all,

Sorry about the delay in responding.

My NP-90M battery pack is working as it should. The issue I had with the side button was sorted. There was a minor connection issue. I'd misaligned an internal component.
So my NP-90M works perfectly and it's got 13 x new NiMh batteries in it.
I'm using the original NC-90M to charge it. This charger is NiCd charger.
My NP-90M currently reads 18.6v across the terminals.
Can anyone suggest what the optimum charge should be for this battery pack?
Is there any problem with using a NiCd charger to charge NiMh batteries?

regards all.