Jävla Oberheim DXS!

BATTERY BACKUP
The DMX contains a rechargeable battery that maintains power to the
memory even when the DMX is unplugged. This way you can turn off the power
and/not lose your sequences, much like the battery backup in the OB-Xa
Polyphonic Synthesizer. However, the memory in the DMX is much larger, and
as a result a rechargeable Nickel-Cadmium battery is used.
With normal use the battery will rarely be drained completely, since the
battery is able to maintain power to the memory for several weeks, when
fully charged. However, if the battery does become completely discharged,
leave the DMX plugged in and turned on for 14 hours to fully recharge the
battery.

Lät maskinen stå på över natten. Just nu knasar den sig inte.
Batteriet är ju nytt så detta ska väl inte behövas? Ska låna mätutrustning.

Drog ur sladden till den, väntade 5 minuter. Slog på den igen. Nu tappar den minnet igen =P suck

Fixat mätinstrument. Batteriet verkar funka fint i alla fall. Det gamla var också helt okej tydligen =P
Ingen aning om hur man skall mäta inuti. Hittat 2 st "testpunkter" som det står +5 på
Kört mätinst. ena spets mot + på batteriet och den andra spetsen mot +5 punkterna.
Det ger utslag i alla fall.

Utslag när maskinen är på. Stendött när den är avslagen.

Vad exakt är "jord" i detta fallet? Så den ena spetsen på testpunkten och den andra sätter jag vart...?

Och jag som körde ner den andra spetsen i en påse blomjord. Not. He he
Tackar.... ska testa

Nu har jag mätt lite i maskinen. Minnes kretsarna får bara 1,5 volt i avstängt läge.
Dom ska ha mellan 2,7-3 volt.

"See the attached photos. Measure the voltage between ground and one of the memory ICs as shown in the large image. You should get somewhere between 2.7 and 3.0 volts at pin 24 of the memory chips. If you get less than this, there may be a broken or bad diode.
The Stretch has another memory IC on its circuit board (see the smaller photo). You should see the same voltage on pin 24 of this IC as well."

Fick lite tips av Paul på electrongate.

Jorå den är socklad som tur är. Vad gör denna lilla krets?

Den ger utslag på 1 volt.

Mera info från Paul:

"I measured the voltage on the dx parts memory IC's and they are only showing 1,5 Volt
when the machine is turned off. The mem IC on the stretch part also only shows 1,5 Volt.

This is a bit too low to hold the memory properly. I think this is where the problem lies.

I measured the voltage on the +5 test points (+5 and ground) and they are not showing any voltage at all when the machine
is turned off.

This is normal.

So, I think that you may have a bad IC connected to the +5M power supply (battery power) that is drawing too much current and causing the voltage to be low.
You can measure the battery current by placing your voltmeter directly across R793 -- this resistor is located just in front of the battery. It doesn't matter which lead of the voltmeter goes left and right. You will just get a negative reading one way and positive the other. What we really care about is the magnitude of the reading. This reading can be divided by 10000 (the resistor value in ohms) to get the actual current, but we can skip that step here. A good voltage reading would be about 0.010 volts, up to about 0.100 volts. I'm guessing that you will see more than 1.0 volts across this resistor, indicating that one of the memory chips is drawing too much current and making the +5M supply drop to 1.5v instead of 3.0v, where it should be.

If you do see 1 volt or more across R793, try removing (carefully) the memory chips from their sockets, one at a time, and seeing if the voltage on this resistor drops to its correct value. If you see a sudden drop in voltage after removing one of the ICs, you have most likely found the bad chip.
In addition to the RAM chips (U405 on the stretch board, U716, U717 and U718), try removing U724 and U725 which are also powered by the +5M power supply.

Another possibility is a bad diode (D709), or contamination on the circuit board that might have been caused if the old battery leaked onto the board at some point. Do you notice any signs of corrosion near the battery?"

Argh. Nu har jag plockat ut alla kretsar en efter en. Tagit ur en, mätt, stoppat tillbaka.
Jag får 3,3 volt på ena änden av R793 och 1,5 Volt på andra änden. Inget av dessa värden ändrades
efter urplockande av alla ovanstående kretsar.

Ser inga spår av batteriläcka heller.

D709 visar 1,5 Volt på båda sidorna.

Måste nog köpa mig en ny Multimeter. Min har jag lånat av farsgubben. Jag lovar att den
är en kvarleva från andra världskriget =P

Känns väl ganska onödigt va? Har ju redan en fin rackare och den ska lagas.
Ska försöka få tag i komponenter idag och byta de 2 dioderna + motståndet.

Mera info från Paul:
"Diode D708 could be bad. Reverse current leakage here would cause extra battery current to flow. If I had the machine here, this is the first thing I would check.
Maybe the resistor R793 itself is broken. If you push on it with your finger, it should not move.
Or, maybe there is a bad capacitor (C709, C713, C714).

Did you happen to try removing the big ribbon cable where it plugs into the socket U715? It might isolate the problem to the Stretch circuit board...

It's starting to look like some soldering may be required to fix this problem."

R793 tror jag blir bäst

Satan! Har ny bytt båda dioderna + motståndet. Den rackarn vill inte ge sig ändå =P Nu åker den snart iväg till Dr SynthX här på forumet som försökt hjälpa mig
online istället.