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litlgeezer · 07-30-2018, 07:34 PM

I have a Dometic Americana Refreigerator . I have just replaced the lower circuit board with a Dinosaur replacement. I have succeeded in getting it back to work as designed. However, I still have 2 red wires coming from the Thermofuse on the stack that I am not real certain as to where each is suppose to land. Does one wire connect to J3 terminal ('Heater') and the other to 12V +?

Thanks.

Old-Biscuit · 07-30-2018, 10:38 PM

12V POS from Fused circuit goes to the terminal block (12V NEG also to terminal block)

12V + RED wire goes from terminal block to the 'thermal fuse' on stack
12V + RED wire goes from 'thermal fuse' to circuit board at J1
(Thermal Fuse part of Dometic Recall-----added to shutdown ALL DC to circuit bd IF it trips)

12V - BLACK from terminal block goes to Ground Point

Board part number 3850415013
P1 To upper control board
P2 Thermistor
P3 To gas valve, igniter and DC heater relay if 3 way
J1 Positive 12V DC from terminal block
J2 To interior light and climate control.
J3 To auxiliary fan (S.) and/or ice maker heat tape
J4 Negative lead from thermocouple
J5 AC line voltage (Black)
J6 AC neutral line (White)
J7 AC neutral out to AC heater
J8 AC line out to AC heater Switched side
J9 Positive wire from thermocouple
J10 Negative to Chassis ground

'Pinout' diagram for Dino Bd 3850415.01
http://dinosaurelectronics.com/Pinou....01_pinout.pdf

litlgeezer · 08-01-2018, 08:25 AM

Old Biscuit,

Your instructions were comprehensive and very understandable for a novice electronics person like myself. Sometimes I get tunnel visioned and you gave me a fresh view of the numerous terminations. Your separated instructions regarding the Thermal Fuse were especially appreciated and helped me grasp the function of this Fuse.

Prior to reading your post, I had managed to get the wiring corrected to the point that the refrigerator was back working properly, although the Thermafuse (high temp sensor?) leads were not connected, which precipitated this thread.

I have two questions;

1. You stated that one red wire goes from the Fuse to J1, then you listed J1 and 12V DC terminal as being connected. Would not this defeat the purpose of the FUSE wire by having a separate wire going to the hot side of the DC block?

2. I tested the red leads from the Thermal Fuse and there was NO continuity. After having pressed the middle reset button on the Fuse, I should have a complete circuit (similar to other fuses)? This Fuse may have been my problem all along. Or, in the past someone may have bypassed the defective Fuse and consequently the circuit board was damaged later.

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Also, I have attached a photo of some thing that was glued to the cover of the old Dometic circuit board cover. I don't know what it is and Dinosaur instructions do not reference it. Is this something related to the ice maker operation? Whatever it is, the refrigerator works with or without it being re-connected (I previously removed the ice maker due to a busted water supply line).

Thanks,
John

Old-Biscuit · 08-01-2018, 12:22 PM

FUSED 12V DC + from DC Dist goes to the terminal block (supplies DC Power)
From the terminal block the 12V DC + goes to the thermal fuse THEN from thermal fuse to circuit bd at J1 terminal
Thermal fuse TRIPS on high temp due to lack of coolant flow....overheating which WILL damage cooling unit. When reset should have continuity thru it.
Typically when the thermal fuse trips the cooling unit is BAD

In order for fridge to have DC it goes from a fused circuit to terminal block to thermal fuse to circuit bd.
Thermal fuse trips...NO DC to fridge ----no fridge functions

That should be the re-ignitor unit used on early year models.
Not used with Dino Bd replacement

Ice Maker.......120V AC