Topic: Dead ISS

[Garth Bock]

The university's ISS stopped transmitting. I got maintenance to get it down off the pole for me. I was thinking this was just the dead battery syndrome which it did have. I have it setting here in the office with me for cleaning and testing. Thing is I know the supercap ran down. I was hoping that ambient light from the window would atleast give me a few minutes of transmission during diagnostics. I pull the lithium and transmission stops immediately. I called Davis and they said the ISS won't run with the lithium pulled. Is there a way to test the supercap to find out if it is charging ?

[talbert1952]

Take the plastic cover off the ISS board and look at the capacitor. If the capacitor has crud growing around the leads you definitely need to replace the capacitor.

[Garth Bock]

Thanks so much ! I want to eliminate it as the real failure of the battery. Davis said the battery would last 8 months so if it failed again it would be in the summer. Not my idea of full diagnostics. Before the snow flies I want to make sure the ISS is fault free. I don't want to send one of our union guys up on the lift in the middle of winter. That wouldn't go over well......

[talbert1952]

If the super capacitor is bad a new CR123 battery will last a few days at best. The bad capacitor kills the battery. You can get a replacement super capacitor from Digikey.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=589-1002-ND

[92merc]

Is that a VP2?  Reason I ask is my VP1 has a disc shaped cap instead of the can one.  Anyone know where you can get those?

[talbert1952]

Is that a VP2?  Reason I ask is my VP1 has a disc shaped cap instead of the can one.  Anyone know where you can get those?

Yes it is a VP2.

Does your capacitor have any markings? The value, voltage rating and manufacturer would be very helpful for finding an exact replacement.

[Garth Bock]

If the super capacitor is bad a new CR123 battery will last a few days at best. The bad capacitor kills the battery. You can get a replacement super capacitor from Digikey.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=589-1002-ND

Super cap had leaked. Ordered a new one and a new lithium. Thanks for everyone's help !

[92merc]

Mine shows 5.5v and 1.0F.

[talbert1952]

Mine shows 5.5v and 1.0F.

Digikey stocks disk type super capacitors.
http://onlinecatalog.digikey.com/WebProject.asp?BookCode=dus08flx&SectionIndex=0&PageIndex=1544#

[92merc]

Looks like the one for the VP1 is on page 1545, top left.  Panasonic SG Series Gold Capacitors.  Electric Double Layer Capacitors.  Vertical Mount.  5.5V 1F

DigiKey PN P6975-ND
Panasonic PN EEC-S5R5V105

$4.82 for one
$3.84 in a lot of 10