Defrost boards cost between $14-$80.  That is a wide range so the repair
price would be anywhere from $45-$185 or so.  I've included the prices of
most of the defrost boards out there.
Phone: (757) 506-6488
There are direct replacement boards that I can order for the following brands
and part numbers.  The price is what it cost me minus shipping and labor of
course.

Direct replacements for specific OEM defrost boards. Features include low cost,
time/temperature defrost, pin-selectable interval times, test pins reduce test time by
256x and stable pin post construction,

ICM300C
Price $19.50 - replaces Amana C64301-1 & C64310-1, Arco 3432140 &
32312-00, Artesian 10321-00, Carrier 621, Coleman 3030A374, Essex 621-1 thru
621-11, Essex 621-310, Heil Quaker HQ1052757, Intertherm 6208800, Goodman,
Janitrol B12260-06, Lennox 33G9501, Robertshaw Uniline DT2-1000, Rheem-Ruud
47-21776-01, Snyder General 1395-329 and Weatherking 840-4-5548. Specifications:
SPST normally open, 2 amps, 10 min. fixed +/-5% defrost. Interval times: pin-selectable
30/60/90 min.

ICM301C -
Price $14.00 replaces Rheem 47-21776-06. Specifications: SPST normally
open, 2 amps, 10 min. fixed +/-5% defrost. Interval time: pin-selectable 30/60/90 min.

ICM302C -
Price $43.00 replaces Nordyne 621301A, 621579B and 621579C.
Specifications: SPST normally open, 2 amps, 10 min. fixed +/-5% defrost. Interval time:
pin-selectable 30/60/90 min.

ICM303C -
Price $70.00  replaces York/Coleman 9218-374, 9218-3741 and
03101251000. Specifications: SPST normally open, 2 amps, 10 min. fixed +/-5%
defrost. Interval time: pin-selectable 30/60/90 min.

ICM304C -
Price $40.00  replaces ICP/Heil/Arcoaire 1069364. Specifications: SPST
normally open, 2 amps, 10 min. fixed +/-5% defrost. Interval time: pin-selectable
30/60/90 min.

ICM315C -
Price $42.00  replaces Avion DFT100 and Ranco E15. Specifications:
SPDT normally open - 20 amps, normally closed - 10 amps, 10 min. fixed +/-5%
defrost. Interval times: pin-selectable 30/45/90 min.

ICM316C -
Price $34.00  replaces Trane CNT1642, CNT1152 and 21C142827G01.
Specifications: 2 amps, 10 min. fixed +/-5% defrost. Interval times: pin-selectable
50/70/90 min.

ICM318C -
Price $27.00  replaces GMC/Goodman/Janitrol B1226008. Specifications:
2 amps, 10 min. fixed +/-5% defrost. Outdoor fan relay output: 1 hp fan @ 240 VAC.
Interval times: pin-selectable 30/60/80 min.

ICM320C -
Price $49.00  replaces Carrier HK32FA006. Low cost, time/temperature
control. Specifications: SPST normally open, 2 amps, 10 min. fixed +/-5% defrost.
Outdoor fan relay output: 1 hp fan @ 240 VAC. Interval times: pin-selectable 30/50/90
min.

ICM321C -
Price $55.00 replaces Carrier CES01130063-00 and CES01130063-01.
Specifications: normally open - 20 amps, normally closed - 10 amps, 10 min. fixed
+/-5% defrost. Interval times: pin-selectable 30/50/90 min.

ICM 322C -
Price $  84.00  replaces Carrier # CES0130024-00. Specifications: SP-ST
Normally open -1 amp, 10min.Fixed defrost time.Outdoor fan relay output: 1/2hp @
240 VAC. Interval times: pin-seletable 30/50/90 minutes.