Hottop Upgrade

by **simonp** » Sat Apr 13, 2013 12:24 am

It seems the PCB mounted fuse prior to the bridge rectifier has gone, so no supply to the low voltage stuff. I can't see anything wrong with the supply after that so perhaps we just had a voltage surge though fuses usually go for a reason. My internet router did throw a wobbler at a similar time to plugging in the Hottop so could be a mains issue. I'll just have to get another one and see, you have to buy them from Farnell in packs of 10 of course :roll:

As I've had to half strip the machine I might as well do the thermocouples whilst the thing is in pieces, though I now have the problem of a rather low coffee supply and no roaster :shock:

by **GreenBean** » Sat Apr 13, 2013 8:05 am

simonp wrote:Hmm, how ironic is this? I just went to roast some beans and the Hottop is totally dead.... Something had failed on the main board and no supply is getting to the control board! Not impressed that the new boards have failed after about 10 roasts. Unfortunately the extra board for the computer control need the original control board to be still working so now I am a bit stuffed. To add even more irony, the second pair of upgrade boards (sent in error) have just gone back to Taiwan....

simonp wrote:It seems the PCB mounted fuse prior to the bridge rectifier has gone, so no supply to the low voltage stuff. I can't see anything wrong with the supply after that so perhaps we just had a voltage surge though fuses usually go for a reason. My internet router did throw a wobbler at a similar time to plugging in the Hottop so could be a mains issue. I'll just have to get another one and see, you have to buy them from Farnell in packs of 10 of course
As I've had to half strip the machine I might as well do the thermocouples whilst the thing is in pieces, though I now have the problem of a rather low coffee supply and no roaster

Oh what a pain, it must be very frustrating.

I am sure that Shelly at Hottop will sort it out for you if you contact her. I assume from what you say that the roaster is completely dead with no sign of life from any LED's on the power board.

The power board supplies a 5 volt supply to the rear fan, bean cooling fan and the bean stirrer motor as well as the control panel. I have only heard of one other user having similar problems and in his case the bean cooling fan had failed and shorted out which caused failure of the 5 V power supply (I think the voltage regulator failed). I suggest you test the fans and stirrer motor to ensure they have not failed/shorted and/or disconnect them before trying the repaired board.

simonp wrote:...The silicone is rated to 220 so add you say will need an eye keeping on. I plan for it to only just come through so hopefully it will be OK.

I am almost certain that it will be fine. The rating of 220 C will be for continuous service and it will only ever see temperatures slightly above that for very short periods of time.

by **simonp** » Sat Apr 13, 2013 10:48 am

GreenBean wrote:Oh what a pain, it must be very frustrating. I am sure that Shelly at Hottop will sort it out for you if you contact her. I assume from what you say that the roaster is completely dead with no sign of life from any LED's on the power board.

The power board supplies a 5 volt supply to the rear fan, bean cooling fan and the bean stirrer motor as well as the control panel. I have only heard of one other user having similar problems and in his case the bean cooling fan had failed and shorted out which caused failure of the 5 V power supply (I think the voltage regulator failed). I suggest you test the fans and stirrer motor to ensure they have not failed/shorted and/or disconnect them before trying the repaired board.

Yes, totally dead, but with the fuse in front of the bridge rectifier gone not surprising. I will get out by bench power supply and check the fans and the control panel board to make sure they are OK. The rear fan is a 12V one isn't it though? Is that run from 5V? There is a switched mode power supply which then looks to be sub-regulated to 5V with a liner reg so I presume the switching PSU drops to 12V for the fans but I will look further.

On the plus side it is striped down ready for drilling for the thermocouples to go in

by **GreenBean** » Sat Apr 13, 2013 11:10 am

You are probably correct Simon. I should have said low voltage rather than 5 volt. I have never had a problem with any of these components so have not looked into this. It is unfortunate that Hottop have not released any circuit diagrams or specs for the relevant components.

by **simonp** » Sat Apr 13, 2013 11:37 am

GreenBean wrote:You are probably correct Simon. I should have said low voltage rather than 5 volt. I have never had a problem with any of these components so have not looked into this. It is unfortunate that Hottop have not released any circuit diagrams or specs for the relevant components.

I don't like giving out circuit diagrams of my designs either so I can't complain :wink:

What I said was correct upon examination. I can't find any issues so unless there is a problem with the switched mode supply when it is powered I think it may just be a random failure. That or the rear fan drew too much current as it is a bit clogged again.

by **simonp** » Tue Apr 16, 2013 12:07 pm

Spacers before and after applying the JB Weld.

I have trial fitted the thermocouples and the silicone tubing works well and holds them in steady.

Also today my boards have coem for the computer contro, and the fuse to replace the failed one. Hopefully it was just the fuse...

by **GreenBean** » Tue Apr 16, 2013 1:55 pm

simonp wrote:Spacers before and after applying the JB Weld.

I have trial fitted the thermocouples and the silicone tubing works well and holds them in steady...

It is good to see it coming together.

simonp wrote:...Also today my boards have come for the computer control, and the fuse to replace the failed one. Hopefully it was just the fuse...

I will keep my fingers crossed, you deserve some good luck now.

by **simonp** » Wed Apr 17, 2013 12:07 am

GreenBean wrote:
simonp wrote:...Also today my boards have come for the computer control, and the fuse to replace the failed one. Hopefully it was just the fuse...

I will keep my fingers crossed, you deserve some good luck now.

Soldered in the new fuse and tested the board on the bench and it all seems to work fine

by **GreenBean** » Wed Apr 17, 2013 10:18 am

simonp wrote:....Soldered in the new fuse and tested the board on the bench and it all seems to work fine

Great news.

Now for the fun bit, getting it all back together and experimenting with computer controlled roasting.

Or is the fun bit roasting and drinking good coffee again? :wink:

by **simonp** » Thu Apr 18, 2013 8:07 am

GreenBean wrote:
simonp wrote:....Soldered in the new fuse and tested the board on the bench and it all seems to work fine

Great news. Now for the fun bit, getting it all back together and experimenting with computer controlled roasting. Or is the fun bit roasting and drinking good coffee again?

For me, both though perhaps the latter wins :wink:

The re-build will have to wait though as we are off to Italy for a week

I wonder if I can find good coffee in Lombardy & Vento?

by **CakeBoy** » Thu Apr 18, 2013 4:22 pm

You stay here, we woudn't want you to suffer! Perhaps one of us could bear the burden of Italy in your stead? Meanwhile you can stay at home and enjoy decent coffee :-)

Oh, go on! ;-)

by **bruceb** » Thu Apr 18, 2013 9:30 pm

Oh man! You can drink good coffee at home. The food! The food! Enjoy it to the fullest (so-to-speak).

by **simonp** » Thu Apr 18, 2013 11:39 pm

CakeBoy wrote:You stay here, we woudn't want you to suffer! Perhaps one of us could bear the burden of Italy in your stead? Meanwhile you can stay at home and enjoy decent coffee Oh, go on!

It is OK, I will grin and bear it :wink:

by **GreenBean** » Fri Apr 19, 2013 7:26 am

simonp wrote:
CakeBoy wrote:You stay here, we woudn't want you to suffer! Perhaps one of us could bear the burden of Italy in your stead? Meanwhile you can stay at home and enjoy decent coffee Oh, go on!

It is OK, I will grin and bear it

It is humbling to see such heroic stoicism.

by **simonp** » Fri May 03, 2013 10:47 pm

I did my first roast today after fixing the Hottop and with the thermocouples installed, also the TC4C & HTC boards, though not using those as I haven't had time to play with Roastlogger yet.
Things went well apart from the bean mass temp readings became rather lower than they should be towards the end of the roast.
Upon examination after the roaster had cooled I found that the bean mass thermocouple seemed loose. When I took the lid off I found that the heat has caused the JB Weld to come off of the back wall meaning both of the spacers holding the thermocouples are no longer attached. A bit of a disaster! I guess the surface of the metal was not clean enough or rough enough, though the attachment seemed secure enough before the machine got hot. I guessI'll have to try it all again.... :cry:

Hottop Upgrade

Who is online