Need some help with a couple of questions

[Guest KevinShea]

Hey all,Really enjoying flying the 737. I have a couple of areas that I need some help on.First, after starting up cold and dark and going thru the checklists that came with the manual when I am sitting there with the APU on the instruments all seem to disappear like they lost electrical power. I can't seem to do anything to get them back on. However, if I press CTRL-E to do a start sequence they come back on. Any ideas?????The second question that I can't seem to find any info on has to do with the AC and DC metering panel. What position should the AC and/or DC meter selector switch be in. I figured the AC meter switch should be on APU GEN when using the APU and then over to GEN1 or GEN2 when the engines are running. Is this right and what should I be doing with the DC meter selector? And what does TR1, TR2, and TR3 stand for anyway?Thanks,Kevin S

[Guest Ray CYYZ]

Your first question is the ole batter problem, preflight with the sim paused or get yourself the full version of FSUIPC.Second question I'll leave to Ian as I have no detailed info on the 737 yet.Ray

[Guest KevinShea]

OK, thanks Ray. I am assuming you mean the 'extend battery life' issue that you can check with the full version of FSUIPC?Kevin

[Guest Ian_Riddell]

"Second question I'll leave to Ian as I have no detailed info on the 737 yet."You're out of luck, here, too, I'm afraid Kevin/Ray..... I can't say I've noticed which positions the switches are in. If we (engineers) had to use them for maintenance purposes, we would simply put them where we wanted them.... returning them to their last position after we had finished with them.TR1, 2 and 3 are simply "Transformer-Rectifiers". These provide DC (direct current) power to aircraft systems. All aircraft require some source of DC power. This can come from a battery, but, normally, Main Battery power is not used on an aircraft (otherwise the battery would go flat like any battery would). Instead, AC (Alternating Current) power, produced by the APU generators, Engine Generators or External Power Unit is converted to DC. This is done with the TR's. This same DC (coming from the TR's) is often used to recharge the Main aircraft battery, in the unlikely case you should need it in flight.Even though the Main Battery is not used, in most cases, the battery Switch is left on, just in case something should happen to the AC power supply... AND, in some cases, the Main Battery Switch provides a vital "power interlock". On the Classic 737 and on the NG you need to turn on the Main Battery Switch to allow External Power to be connected to the aircraft electrical system (This is not currently modelled in PMDG). On the Classic, the Main Battery Switch has to be left switched on as switching it off will trip off External Power (confirmed this yesterday). On the 737NG, however, I hear that it is not necessary to leave the battery switched on to leave External Power hooked up.Hope this helps.Cheers.Ian.