Alternator out warning board - Page 2

Mark Hislop · #16 01-30-04, 05:15 PM

Peter:

I'll look it up tonight, and post it for you, assuming the4 part number for a '73 P model is the same as for yur aircraft.

Mark

kevin · #17 01-30-04, 05:52 PM

Pete,

I found the alternator warning board in my maintenance records. I have a part number of 1570059-1 on a '73 P337. Cost was $965 in 2001. Don't know if that will help, and I can do nothing to verify the part number.

Good luck,

Kevin

Mark Hislop · #18 01-31-04, 01:45 AM

Kevin and Peter:

The way I interpret my drawings and service manual, the part number that Kevin refers to, 1570059-1 is just for the diode assembly (diode and heat sink). If I am right, you can buy the diode from Radio Shack or Newark electronics for less than $75. This is what I did when I had to replace my diodes, thanks to advice from GMAS. The price I got at the time from Cessna was about $750 (can you believe it?).

I think the part number for the circuit board assembly is actually 1570304-1, based on the schematic drawing. I have no idea if by the word "assembly" they mean that there are other components mounted on the board, or if it is just a circuit board. The drawing isn't very clear to me, but this part number is the only part referred to as a circuit board assembly on the drawing which shows the alternator wiring diagram.

Perhaps with these two part numbers you can call a Cessna dealer and at least find out which of these part numbers (if any) is correct.

Sorry to not be more sure of my answer, but hopefully this is a starting point for you.

Mark

Ernie Martin · #19 01-31-04, 11:57 AM

I have some advice on the printed circuit board, but let me first make an observation. As an aerospace engineer on my second Skymaster, I have been following this thread with considerable interest because of its insightful content. Especially the two comments from Kevin: first, that the original warning lights are too important to discard, and second, his theme (to which I'll add a little spin) that the electrical system is too complex and too weak for us to be modifying it.

My main suggestion to Peter is that the printed circuit board and other components which you are seeking might be found in good condition -- and at huge savings -- from parted-out Skymasters which spent most of their life in arid regions. The "Purchasing Parts" page of my Skymaster website at www.SkymasterUS.com gives detailed directions on buying used parts successfully and provides the names and contact info of suppliers. I would start with Don Nieser at Commodore.

Also, to make sure that you have the right part numbers, you may need the aircraft serial number; this is particularly true if yours is a French-built Skymaster. Finally, the optimum approach is for you (not someone else) to look at the Illustrated Parts Catalog, so that you can choose from the illustration all of the parts you need and their part numbers, and to make sure that those part numbers apply to your aircraft serial number.

Ernie

DHatfield · #20 01-31-04, 06:26 PM

Pete,

I also installed an EI-VA1 volt-ammeter with the three-way switch for front, rear and battery current. I left the factory warning circuitry in place. I happen to have a picture of the shunt installation that I took when the front engine was out for replacement recently. You can see that I installed the shunts by stacking the front regulator on top of the rear regulator with spacers for cooling. I then made an aluminum plate with mounting holes that matched the regulator and attached the three shunts. I then built a bracket to hold the 6 required fuses.

My skymaster has de-ice boots, making firewall real estate very valuable. This was about the best layout I could come up with.

David

Richard · #21 02-01-04, 03:36 AM

I added a quad gauge that includes Volts, Battery amp draw, Front alt output, and rear output. Giving you a visual without having to flip switches.

Pete Somers · #22 02-01-04, 06:39 AM

Thanks everyone

I did not expect that amount of replies!!

The concusion it that-
Although installing the EI type indicator eliminates the ammeter, there does not seem to be a mod to get rid of that PC board and the troublesome relays, ah well never mind i will try and get a new or used unit. Well it did give Mark something to think about!!!

I will try your site Ernie, thanks.
The 337 electrical system is very easy, the main problem is people think is complex, as an (out fo work) Avionics eng with 30 years experiance and the Cessna courses (including 337 electrics) i have a little head start.

I will have to think about a unit that will replace the ALT out board at a later date.

Again many thanks
Peter

Richard · #23 02-01-04, 03:11 PM

I've always wondered, what would be the problem with running each alt. on it's own regulator?

Pete Somers · #24 02-02-04, 04:47 PM

Richard.

On the models 337G and above they do run separate regs for each alt, but not on your 337B.

Peter

sgettings · #25 05-29-09, 05:29 PM

The PN on my 73 337G is:
1570057-1 Rev A

DBrugg · #26 06-01-09, 03:23 PM

my parts catalog for '73-'80 P models shows part no. C593004-0101 for the description "sensing assembly-over & under voltage". To me it's not clear if this is for the circuit board or not. I have left the warning lights "dumby lights" and added the EI volt/amp meter for trouble shooting. I had rebuilt the warning board by replacing all the electrical components and attched a diagram with part numbers for the diodes and relays to an earlier post.
Dan
________
Buy Vaporizer

bking · #27 04-25-21, 09:53 AM

Hello all, does anyone have a current part number for the(2)REED RELAYs as shown on the "Schematic Alternator Warning" wiring diagram, drawing# 1571000 in the service manual? The part numbers (PN300-884-9944) on my relays are now obsolete.

I have called Don Nieser and several other sources without success so any help/ideas would be a greatly appricated.

Thank you,

BK

hayesjaj · #28 04-27-21, 12:03 PM

I think the unit you are looking for is 1570058-1 (Figure 134 of the IPC, 73-80). Cessna has 5 of them, $1423 ea.

bking · #29 04-27-21, 12:08 PM

Thank you for the info.

Learjetter · #30 04-27-21, 02:33 PM

Quote:

Originally Posted by bking

Hello all, does anyone have a current part number for the(2)REED RELAYs as shown on the "Schematic Alternator Warning" wiring diagram, drawing# 1571000 in the service manual? The part numbers (PN300-884-9944) on my relays are now obsolete.

I have called Don Nieser and several other sources without success so any help/ideas would be a greatly appricated.

Thank you,

BK

I rebuilt the entire board on my '77 NA G model, and replaced the reed relays with new from the manufacturer, Computer Components Inc.
1-800-653-9909 Part#300-884 (x2). ($75 each, plus $17 shipping).
www.relays-unlimited.com

If you're going that far, recommend replacing the diodes and resistors too.
There are a couple posts in the forum discussing the modern equivalent part numbers and sources.