Part #:

Model: PS-835D

L3Harris - Emergency Power Supply
Part Number :
L3Harris Logo

  • A nominal 24Vdc Emergency Power System, which when combined with optional modules will supply 24Vdc, 115Vac 1O or 3O, 400Hz, and 5Vac, 400Hz or 24Vdc, and 5Vdc
  • The optional modules include: SI-100, SC-841, BC-815, or MTG-101A
  • The system may be tailored to provide power to an emergency attitude indicator and/or transceiver, lighting, etc
  • In the event that aircraft power fails, the batteries of the PS-835 take over the duties of supplying DC power to the plug-in module and any external loads without interruption
  • PS-835D has met STC requirements for installation on the Learjet 20/30 Series aircraft, and STC requirements for Learjet 50 Series aircraft
  • Contains sealed lead-acid batteries having a rating of 5.0 ampere-hours at the 10 hour rate
  • Consists of a chassis, two circuit card assemblies (CCAs), and assorted hardware
Dimensions: 7.626"H x 14.114"L x 2.282"W Weight: 13lbs
Input Voltage: +28-30Vdc Output Voltage: +24Vdc (nominal)
Altitude: 55000 ft Temperature: -55C to +70C
TSO: None exists    
Part Number Emergency Power Supply Description:
501-1228-04 See Details Above


- Emergency Power Supply

NSN: 6130-01-219-8285

Price Condition Delivery

SEA Repair Capabilities: Yes

- Battery Cell
Price Condition Delivery

SEA Repair Capabilities: No

Click on a question below to see the answer. If you have a question about this model that is not answered below, please contact

Southeast Aerospace exchanges are based on the return of an undamaged, economically repairable core unit with identical part number as the unit shipped to the customer. An "economically repairable" core is defined as one where the cost to repair/overhaul (or Repair Cap) does not exceed 80% of the original SV/OH exchange price billed. Should the Repair Cap exceed 80%, the customer will be billed the additional amount. In the event this amount exceeds the Outright Price for the unit, the customer would only be billed the difference between the Outright Price and SV/OH Exchange Price with the core returned as-is to the customer.

Here is an example of such a transaction:

$1000 Exchange Price charged to customer
$1000 x .8 = $800 Maximum Allowable core repair charge or Repair Cap

$2000 Cost to repair core unit
- $800 Less Core repair cap
$1200 Additional billing amount.

2200.00 Total Cost of transaction

Please Note:
SEA offers exchange on new items as well. However, repair cap as indicated above is still based on SV/OH exchange price.

The Mid-Continent TS835 is a lighter weight alternative for the PS-835 power supplies. The TS835 weighs only 4.5 pounds while the PS-835 weighs 13 pounds. The TS835 has a battery life expectancy of 10 years. No rewiring or changing of the mounting rack is required when upgrading to the TS835 from the PS-835. Certification of the installation is not affected since TSO'd parts are being interchanged.

Negotiating the exchange price of a unit only limits the allowable repair cap for the core unit. Southeast Aerospace's exchange transactions are based on the return of economically repairable core unit. Once the core is received and evaluated, the core repair cost incurred by SEA cannot exceed 80% of the original exchange price. That is, it cannot cost SEA more than 80% of the original OH/SV exchange price collected from the customer. Therefore, when and if an SEA exchange price is discounted, there is a risk that additional charges may be assessed once the core is returned and evaluated.

For more information, please refer to these other Exchange FAQs

According to L3 Service Letter SL-80 (Rev. W), the condition of the batteries should be checked every 3 to 6 months according to the Periodic Check procedure outlined in the bulletin. If the "Voltage Level 24VDC LED" does not illuminate while the 20VDC is illumined, then the unit is incapable of providing emergency power. The "Cell Isolation Test" must then be performed to identify if the unit requires repair or charging.