attempting to repair my jbc cd-2e station

[nardisk]

I'm trying to repair my jbc for a capacitor loaded at 36v it made a mess, opening the station I immediately found some damaged transistors and I also replaced op07c and with these my t210 works, the problem instead is with the t245 which gives me 350 degrees but the tip doesn't heat enough to solder, I haven't checked what the temperature really is but looking at the diagram I can't understand the problem, my idea is to replace 74hc4053 because it seems that it is connected directly to the tc because the damaged components that I replaced and found faulty were on the tc line. Do you have any idea why the 210 works well and the 245 doesn't?

[Kean]

It appears the C210 and C245 use different wiring schemes, so I believe the 74HC4053 should be getting different control signals to switch the TC connections.

See this post: https://www.eevblog.com/forum/testgear/jbc-soldering-station-cd-2bc-complete-schematic-analysis/msg3325198/#msg3325198

[nardisk]

yes I noticed that the wiring is different, before my intervention I had the t210 that heated the tips endlessly until they became incandescent, through a thermal imaging camera I see the 74hc4053 a little hot which I don't know if it's normal 

[Kean]

That is not normal in my experience - but it depends how "little" hot it is

[Electro Fan]

yes I noticed that the wiring is different, before my intervention I had the t210 that heated the tips endlessly until they became incandescent, through a thermal imaging camera I see the 74hc4053 a little hot which I don't know if it's normal

What was the initial failure or cause that started things needing repair?
A little off topic but what thermal camera make/model are you using?

[nardisk]

I dismantled the station again to check the temperature but I must have been wrong but now there is no heat.
The replaced components are: 2 bc847a  1 op07c 1r475
1 bc858b but I only had the bc857b I don't know if that's why?
as said the t210 works very well the t245 instead is at 350° but I think it is not because the tin does not melt if I raise it to 450° you notice a bit of smoke but it still struggles to melt the tin 

[DaneLaw]

https://www.eevblog.com/forum/repair/

*Ask for repair help or describe how to repair equipment

[thm_w]

I asked a mod to move the thread.

OP:
Is the station CD-2BC, I assume, since thats the schematic you are looking at?
Doesn't the station show on the screen anywhere what iron is detected? Is it detecting the 245 as 210 or is it correctly detected?

The 210 is 12V so if its trying to use 245 with 12V it will have limited power.

[tautech]

I asked a mod to move the thread.

The OP can move their thread/topic anywhere in the forum that suits them.
Only Mods and OP's can do this with the OP using the Move Topic feature at the foot of their page.

[thm_w]

I asked a mod to move the thread.

The OP can move their thread/topic anywhere in the forum that suits them.
Only Mods and OP's can do this with the OP using the Move Topic feature at the foot of their page.

You are right, for some reason I thought that was only if no one had responded.

[nardisk]

the station detects the t245 without any problems. yesterday I did a general check, I changed 3 more op07c but nothing changed, the resistors are ok, now I only have to replace the 74hc4053 and the lm358 and then I don't know what to do.
What is the PTC on the transformer for?

[thm_w]

Presumably to monitor the temperature and see if its overheating?

[Original]

the station detects the t245 without any problems. yesterday I did a general check, I changed 3 more op07c but nothing changed, the resistors are ok, now I only have to replace the 74hc4053 and the lm358 and then I don't know what to do.
What is the PTC on the transformer for?

Are you sure you checked in the "Tool settings" menu what is says when you plug the 210 and what it says when you plug the 245?

[nardisk]

exactly as said before it detects perfectly both 210 and 245 in the tool setting menu

[Original]

Weird... As far as is commonly known it checks for the jumper in the plug to distinguish between the two types and conversion happens in software...

The thermocouple amplifiers are common...

[nardisk]

I have already checked the pins and I did another test, I connected the tip with flying wires the result is the same pin 7 9 12.
I found that the voltage -4.5 is not exactly what is generated by the bc858 but a poor 4 volts. I also tried to remove the bc858 and via a bench power supply I gave 4.5 volts to try but no result, if I understood correctly are the 2 mosfets that pass the loader and the com? if I have the t245 connected what voltage should I have after the mosfets? or do I have to connect an oscilloscope?

[nardisk]

guys I replaced the 74hc4053 and lm358 but I didn't solve the problem, can someone help me?
as you said a little more if it sees it as t210 and I get 12 volts my t245 will be limited,
t245 is detected but after the mosfets I don't have more than 12 volts and then I can't control it properly because the voltage is not stable.
I wanted to ask you what the 1.25A smd fuse is
I wanted to add that from the transformer I have 24 volts but after the mosfets they become 12 with both t210 and t245