240-SX Radio Power Problem

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Mardon - 18 Aug 2007 20:33 GMT

The radio in our 1990 240-SX no longer retains its station presets when the
ignition key is turned off. It does retain the settings if the radio is
turned off while the ignition key remains on. It's the original factory
radio only; no cassette or CD player. I've looked for a blown fuse that
might cause this to happen but can't find any. Can anyone suggest how to
fix the problem?

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E Meyer - 19 Aug 2007 01:57 GMT

On 8/18/07 2:33 PM, in article
Xns9990AD92960D2mgb72mgbhotmailcom@194.177.96.78, "Mardon"
<mgb72mgb@hotmail.com> wrote:

> The radio in our 1990 240-SX no longer retains its station presets when the
> ignition key is turned off. It does retain the settings if the radio is
> turned off while the ignition key remains on. It's the original factory
> radio only; no cassette or CD player. I've looked for a blown fuse that
> might cause this to happen but can't find any. Can anyone suggest how to
> fix the problem?

Looking at the wiring diagram for the '91 (yours should be similar if not
identical):

The radio is fed by two fuses. They are not numbered in the FSM, just
pictures of their location in the fuse box:

1. The third one from the top on the right side of the fuse block feeds the
backup memory which normally holds the presets. This same fuse also feeds
all the interior lights and a bunch of other stuff. If the interior lights
still work, this is probably not the problem.

2. The fourth one up from the bottom on the left bank in the fuse block
feeds the switched power. If this one is blown, the radio should not work
at all.

There is also a 7.5 amp fuse on the back of the radio itself. Appears to be
for electronic tuning. You will need to pull out the radio to check it.

If these three fuses are good, then the problem is bad wiring, bad connector
on the back of the radio, or internal problem in the radio. If you pull out
the radio, probe the center pin directly adjacent to the key on the
connector for 12 v. Wire is red/black/ This is the feed for the (always hot)
backup fuse. The second fuse should be coming in at the leftmost pin on the
same row. Wire is blue. This is switched power. Should have 12V only when
the ignition switch is on or in acc position.

I still have the original radio from the '91 in a closet somewhere. The
tape drive is dead, but it otherwise still worked when we took it out. Let
me know if you need it for parts.

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Mardon - 22 Aug 2007 02:11 GMT

> On 8/18/07 2:33 PM, in article
> Xns9990AD92960D2mgb72mgbhotmailcom@194.177.96.78, "Mardon"
[quoted text clipped - 38 lines]
> The tape drive is dead, but it otherwise still worked when we took it
> out. Let me know if you need it for parts.

Wow! Thank you very much for the detailed description. The inter lights
do work and the radio does work normally as long as the ignition key is
not turned off, so it is not the first two fuses you've mentioned. I've
also checked those fues in the fuse box and they weemed OK. I did not
know about the fuse on the back of the radio. That may very well be the
problem. I'll pull the radio and check it. That may take awhile because
we're in the middle of a family situation (my father-in-law is in
pallative care.) When I do pull it, I'll post the results here so you
will know. Thanks for the offer on the radio for parts. We're trying to
keep the care 'all original' since I bought it new. The original radio
did not have a tape deck. If we had bought it with a tape player, the
tape deck would have been a seperate unit that mounted in the console
directly below the radio. Hopefully, the 7.5 amp fues will be the
solution. If not, your description of the 'always hot' wire is a big
help. Many thanks!

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