Alternator replacement

[nialled]

I do not have any mechanical skills so please be gentle.
I bought my 200SX new in Nov 1996. It has been on the road ever since, serviced every year and has not been modified.
Over the last 6 months or so I have noticed a slight squeaking noise just after the engine is started and the sound stops as soon as the fan cuts in after about 30s. The noise is quite subtle but it reminds me of how a fanbelt sometimes sounds when it slips.
Anyway, I do not drive the car very often (sometimes for several weeks) and I am now having issues with the battery not having enough power to start the engine.
I am confident that the battery is not at fault (it was the first thing I replaced when the problem started to happen). I am wondering if the alternator could be failing. My understanding is that they do eventually fail and this one is the original, fitted by Nissan in 1996. It must still be working a bit as the red battery light on dash goes out as soon as the engine starts but I think maybe it is not producing sufficient current to charge the battery properly on the fairly short journeys that I do. Could it just be a slipping belt perhaps?

The part number appears to 23100 65F17, underneath this it has A2TB0591A and underneath that is says 12V 80A 6823
My questions are:

Where can I get a replacement alternator?
Can anyone tell me the specs on the original alternator
Will an alternator from a S13 or S14 be ok or does it have to be for an S14A?
Will any alternator intended for use with the SR20DET be ok or is there something special about the 200SX alternator?
Any help and guidance will be greatly appreciated.

[speedingmofa]

I seriously doubt the alternator would go that soon. Use a multimeter and check voltage levels while idling and raised rpm (3k or so). If it's around 14V, then the alternator should be good, and it's the battery getting weak. Rule of thumb is, to change the battery every 4-5yrs. So if that's the original 1996 battery, it has had a very long life!

If it really is the alternator, any sr20det alternator will do, obviously it has to come off a rwd motor.

On a side note, if you don't drive the car much, and only start up once in a while and don't give it sufficient time to recharge, the battery will go dead over time as it's not getting sufficient time to recharge (+/- 10 minutes driving)

[nialled]

Thanks for the helpful reply. Good to know that any sr20det alternator will be ok.
The battery is not the original, it has been replaced several times since I bought the car; most recently about 12 months ago and it is holding a charge. As a test, I charged it and then left the car for 3 weeks. It started immediately without any issues (the car is normally an excellent starter).
It could be that my short journeys are not giving enough time for the battery to be recharged but the squeaking noise is a fairly recent issue. The more I think about it, the more I am wondering if a belt is slipping

The alternator is the original, ie about 23 years old. I will check the voltage across the battery with the engine stopped and running to see how they compare.
Thanks again

[green_rs13]

id say that an alternator either works or does not work. it does not 'half work' chances are your belt is the culprit try getting another one fitted.

[nialled]

Thanks for the reply. At first, I also thought that maybe it would either work or not work but then I started to wonder what will happen to the output from an alternator when the brushes get close to wearing out. Presumably the output current would drop for a few hundred miles or so before failing completely.
The car only has 74,500 miles and I assume that alternators normally last longer than that but I don't have any experience in that regard.
However, I think your advice makes sense. I will take it to the local garage and ask them to replace the belt. Do you know if there is anything special about the belts? Are they easy to obtain?
Also, should it come to it, does anyone know where a replacement alternator can be sourced?

[green_rs13]

you would probably get a working secondhand alternator off here for about £50. I did refurb an SR alternator last year and it was pretty easy to just pop new brushes in, I bet a decent auto electrician would 'refurb' one for you for about the same amount.

the belt goes round the water pump so its not a bad thing to change it if its old. get them to fit a new power steering belt and an aircon at the same time. belts are about a tenner max each.

[nialled]

I put a meter across the battery terminal and it measured just over 12V (12.25V) with everything turned off. This dropped to just under 12V (11.95V) when I turned on the ignition and lights but WITHOUT the engine running.
I started the engine and measured again at about 1500RPM. The voltage increased to slightly over 14V both with the lights turned on and turned off.
So, it seems like the alternator is working at least enough to power the lights. Hopefully, the noise is just a belt.
Thanks for the suggestion about replacing the belts. I think they are all original (unless changing the belts was ever part of a standard Nissan major service as almost all the servicing has been done by Nissan dealers). I will book into my local garage and ask them to replace all the belts.
Maybe the lesson I should learn from this to take the 200SX out more often!