JBC Soldering Station CD-2BC - Complete Schematic & Analysis

[TheSchilk]

Looking at the schematic again, if there are 245 tips with a series TC, they must have the TC and COM pin shorted internally, otherwise how would the Heater current return through the TC pin?

[Hydron]

I think the diagram of the cartridge in the OP's schematic is slightly wrong (or possibly can be right but isn't always!), as I have measured a few C245s and they seemed to have a series TC, as shown in the diagram in this other thread:
https://www.eevblog.com/forum/projects/yet-another-controller-for-jbc-t210t245/msg3077826/#msg3077826

Similar to the OP's station, my JBC BT-2BWA also only uses the "TC" connection (C1 on the other diagram) for sensing, no substation current flows through it. I just posted a bit more explanation of the operation of this station in that thread.

[johnmx]

Looking at the schematic again, if there are 245 tips with a series TC, they must have the TC and COM pin shorted internally, otherwise how would the Heater current return through the TC pin?

I have more than ten C245 tips, but I only measured a couple of them. I believe they are all exactly like the schematic I posted in the first post.
Do you have any complete model number of such C245 tip with the TC in series?

It would make sense on a station that supports the c210 handle because that handle (again, according to SparkyBG) always uses a series TC.

Am i right that the station you reverse engineered only supports the c245 handle?

  all just speculation thought.

The station model CD-2BC only supports the T245 Handpiece and the C245 cartridges.


I give up on making the controller for the T245 handpiece. Instead I bought a new BT-2BWA for 190€. With the time required to implement such controller I can easily earn many times more than that.

[Hydron]

I measured half a dozen C245 tips and none had a thermocouple voltage present between TC and LOAD (it _was_ present between TC and COM). Note that the thermocouple voltage isn't very large - heating the tip up by hand only gives a few microvolts change.
This suggests that the attachment point of the heater resistance in the diagram is incorrect, at least in some cases. The thermocouple junction is definitely between TC and COM in all cases (in both C210 and C245).
It doesn't really matter however; when measuring the temperature TC and COM are used, which works regardless of where the attachment is and whether the heater current passes through the thermocouple junction or not.

As for T210/C210 compatibility, both the BT-2BWA and the CD-2BC support the T210/C210 in addition to the T245/C245 (it's stated in the manual).

[johnmx]

This suggests that the attachment point of the heater resistance in the diagram is incorrect, at least in some cases.

Which diagram are you referring?

As for T210/C210 compatibility, both the BT-2BWA and the CD-2BC support the T210/C210 in addition to the T245/C245 (it's stated in the manual).

Yes, you're right. My previous statement was based only on the product page.

[Jane]

Anyone knows how much JBC CD-2SQE is different ? How much info from this thread can be used with JBC CD-2SQE?

[RichardSim]

Very interesting - thank you for doing this!

I believe this thread (and all other threads I've found online for that matter) has missed one important part of the schematic with regards to T210/C210 compatibility.

Analog switches controls what signals feed the differential amplifier. When SW1 and SW2 are ‘0’, T_TIP represents the temperature by measuring the small voltage between TC and COM. The circuit is at this state most of the time. One time during power up and one more when the handle is connected, the circuit changes SW2 to ‘1’ during 30 ms. At this point, both inputs are connected to TC. Maybe this is used to see the offset of the amplifiers. Sometimes, especially when the tip temperature decreases, SW1 goes to ‘1’ for 300 us up to 8 ms. Now the amplifiers are measuring between LOAD and COM, this is the voltage drop at the heater.

The one remaining combination is LOAD + TC when SW1 and SW2 are both 1. I believe this will be used for T210 handles as the cartridges are wired differently (LOAD and COM are swapped), so you likely didn't run into it with your testing with a T245 handle. This is fascinating, as in other threads (and earlier in this thread) the general wisdom is that for C210 cartridges the heater and TC have no common tap between them, so every open source JBC T210/C210 controller I've found is powering the heater through the TC (and likewise measuring the TC through the heater)!

Here's a diagram I found in the Unisolder thread over at the Dangerous Prototypes forum. Of note is that the T210/C210 connections do not match anything else that I've found online, however they fit the circuit here as I've described, and more importantly all my C210 cartridges appear to corroberate it. Having said that, I haven't actually hooked the cartridges up to a TC amplifier yet to be able to measure it.

[dungo]

Hi. I appreciate the work you did in making this diagram. It helped me a lot to repair a JBC that I got badly damaged by a short circuit. managed to repair it almost completely. I only miss the part of the PTC in which you have doubts if it is 33k. actually when looking at your diagram I saw that a 2.2k thermistor is needed to form the voltage divider and thus be able to lower the voltage to approximately 2.5v. as this jbc they removed the thermistor from the transformer and I did not find the 2.2k thermistor just put a resistor of that value. I know it is not ideal but I do not have the correct part. apparently everything works perfectly. Thanks again for your contribution.

[Laidukas]

Hello everyone, I would like to buy NT115 nano handle and connect it according T210 pinout, but concern is that T210 is 40W and NT115 is 14W. Does base-unit/controller actively control delivered power to the tip? and consequently will fry the heating element of NT115? Or is it the "Keep It Simple" design where power draw is determined by heating element resistance and I can connect lower wattage tip with no worries?

[thm_w]

Hello everyone, I would like to buy NT115 nano handle and connect it according T210 pinout, but concern is that T210 is 40W and NT115 is 14W. Does base-unit/controller actively control delivered power to the tip? and consequently will fry the heating element of NT115? Or is it the "Keep It Simple" design where power draw is determined by heating element resistance and I can connect lower wattage tip with no worries?

You can find some explanation here: https://github.com/Winkelkatze/jbc_nano_solder

[cpposteve]

Hi

Thanks for your help.

this should help me or at least try to fix my DI-2D. im having an error with mine where it shows error 2 open circuit. have been looking for a schematic for a while now to try and get to the bottom of my issue and to resurrect it. Would you happen to know what part of the circuitry would be monitoring for an open circuit? im thinking maybe the TC input but yet to probe around.

here is a link to my thread as to whats been happening.
https://www.eevblog.com/forum/repair/please-help-me-diagnose-my-jbc-di-2d-fault/


many thanks

Steve

[Ribster]

I’ve had this same issue with the knock off of tips.
Changing the tip resolved the issue

[cpposteve]

unfortunatly not in this case. all my tips are genuine and tested on this machine
 

[Andrew_sokolov]

look at the voltage graph on the heater. I think a PID controller is used with a window of 5 pulses 50 Hz

[c0d3z3r0]

@johnmx Did you try to dump the firmware?