Hey there.

I bought an old broken HotTop 8828P very cheap last weekend, which I am now hoping to repair.
Originally, I had an appointment with a friend who's an electronics engineer today, but since he didn't show up I decided to look into the matters myself.

I found some weird looking small pieces of wire underneath the main circuit board, as well as a resistor that is only soldered to the board in one end.

Can somebody help me figure out whether things in these pictures looks right?

I do not have a spare late-model main board to which I can compare without taking a roaster apart, but that does not look good. The cut black wire at the bottom right corner (5:30 position) has been added by someone- that is not factory. The same for the added resistor at the top. No wire leads are permanently connected to the main board. All connections are by sockets or by spade connections. So just looking at that, someone has been trying to do something-who and what are your guess.

If that were nine (I shudder to think, and I hope it was quite cheap to you) I would test the following:
- main motor
- heating element
- eject mechanism
These all run on mains voltage (110 volts). If those are OK, then it might be a good investment to get a new main board and new control panel as well, and to get the most out of the roaster, convert it to a "KN-8828B."

Now, to go the next step, you can leave the "P" panel and instead of replacing it, add the HTC + TC4C boards, two additional thermocouples, and computer control the roaster through a USB connection. There were problems doing that with the KN-8828P-2K but I think there are folks using it with the KN-8828P. The author of Roastlogger is iirc.

Hey Randy. Thanks for your reply! I paid what corresponds to 120$ for it, so even with a new main circuit board I think it's a pretty good investment. Keep in mind that those roasters are a lot more expansive in Denmark where I live, than in the U.S. - the original price for the roaster was 1317$ for the machine, and 700$ for an upgrade kit to make it the P-model.

Actually, I would like to replace as little as possible and make it work as cheap as possible. To do that, I would like to test the parts you mentioned - main motor, heating element & eject mechanism - as well as the side panel. You mention that the the parts run on main voltage, 110V, but since I live in Denmark I guess that they are made to run on a Danish 230V current? Could I just feed them one at the time, directly from the wall socket? Do I have to figure out what is + and - on each, or is that not necessary cause it's AC?

What about the sidepanel, how would I test that? I guess that it runs on a lower current (12V/24V?), which I might be able to feed it through one of the leads in the mainboard connector?

I appreciate your help, Randy! Actually, I was hoping you would reply to this thread. I've had a couple of different roasters earlier (IMex, iRoast and Gene), and everything I've been looking up roasting information from the Internet, your name seems to show..

Not surprising that my name shows up on Hottop searches- I posted the first review of them about 10 years ago, and I created the Hottop USA website and created the owners' manual (Hottop is a client of my graphic arts business).

Yes, the items I mentioned (Main Motor, Eject solenoid, and Heating Element all run on mains voltage, so if you have the correct model for your country each of those items can be disconnected from the main board and connected to mains voltage, one at a time. Please do so carefully, and insulate each connection before powering up the item.

The control panel runs on lower voltage (DC I believe). I do not know what that would be for you as I have no experience with the 230 volt models (they are not sold here). There is no way I know to effectively test it without hooking it up to a good roaster and using it. The control panel operates all functions as well as containing the memory for saving profiles. The little blue(?) boxes on the main board are relays that the control panel operates to turn things on and off.

Be aware that the heating control of the "P" model is binary (either on or off and that's it). The "B" model uses Pulse Width Modulation (PWM) which gives the user a lot more control over the roaster and makes for a superior roaster in terms of control.

You did get a good deal. That main board would need replacement. I would not trust it regardless.

Thanks again for your kind help and advice. I really appreciate it!!

Actually, I think I heard your name first time when reading about the iRoast2. As far as I remember, someone tried to copy one of your HotTop profiles with the iRoast2!

Well. I guess the next step for me will be to test the parts one by one, and order a new mainboard if that shows to be the only broken part.

Regarding the side panel, I found this post describing the wires in the 8-pins connector:
http://www.homeroasters.org/php/forum/v ... post_40016

I was thinking that I might find a DC converter and use that to supply 5VDC to the black and brown wires. I cant think of a reason that the EU models panel should use a different current than the US one. I am aware that this won't allow me to test every single function on the panel, but dont you think it would allow me to test whether it is able to turn on?

I still have the electronics for my old HotTop D, I upgraded it a couple years ago to the P electronics. I would make you a deal on it but it is for the 110v version which would not do you much good. However, maybe the photos will give you an idea of what a stock board looks like.

Thanks for the kind replies from the both of you, as well as the offer to sell me the parts.

I ended up buying a new mainboard which is supposed to be sent from hottop UK today. It was a pretty expansive matter, but luckily the motor, heating element and solenoid valve works very well, so hopefully this will be the only part to change.

Rasmus.

I am going to pick up my new main circuit board from the postal office tomorrow. There's one thing I don't understand, though..

The picture from hottopusa states where I have to connect the black and the white power wires on the main circuit board. In my case, the power wires are black and brown. But why will it even matter, when its running on AC?

By US codes, the "LINE" (marked "AC-L" on the circuit board - black wire) is connected to the switch side. The other wire is the "COMMON" (marked "AC-C" - white wire). And you are correct. Other than that it doesn't (or shouldn't) matter. There are different European wirings. Since you have a black and a brown wire, refer to this page:
http://inspectapedia.com/electric/Wiring_Colours.php
It seems that the Brown will be your "L." So we can assume that Black is the common (neutral).

Thanks again, Randy!

I guess I wrote it wrong last time - my wires are brown and blue (not black). Will the brown one still be the AC-L?