- Make sure your 42V consumers aren't shorted... TOP PRIORITY as this is the TOP reason for needing to do the following replacement:
- Replace U1 (LM338) on the board, make sure resistors aren't open (infinity ohms) after you remove the LM338 to make it easier to measure them.
It is going to be a challenge to find a regulator that goes higher 36 volts
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *
These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%
1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board
All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
Ok thanks ill buy same part...one note...when this loss of 42v happened at same time a 10a fuse blew near the machine main ac input
I replaced the fuse and has not blown again
At the time i was working on a diff area of the machine...trying to install a potentiometer on a diff board to control rpms of spindle...when i installed the pot and set it at 0rpms the spindle was turning fast...i was like what the heck...so i powered off machine...rechecked pot wires and powered on again and main fuse blew...along with losing my 42v output.
Ok thanks ill buy same part...one note...when this loss of 42v happened at same time a 10a fuse blew near the machine main ac input
I replaced the fuse and has not blown again
So maybe this is related
Do you know what caused the fuse to blow in the first place
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *
These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%
1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board
All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *
These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%
1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board
All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
Ok thanks ill buy same part...one note...when this loss of 42v happened at same time a 10a fuse blew near the machine main ac input
I replaced the fuse and has not blown again
At the time i was working on a diff area of the machine...trying to install a potentiometer on a diff board to control rpms of spindle...when i installed the pot and set it at 0rpms the spindle was turning fast...i was like what the heck...so i powered off machine...rechecked pot wires and powered on again and main fuse blew...along with losing my 42v output.
****
Maybe this is all related.
***** Dose this have a PWM speed controller for the spindle or is this Servo motor controller with a power supply build into the drive
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *
These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%
1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board
All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
hmm that looks like it's on backorder too, but probably easier to get that way than mouser.
Seems you can only get the TO204 version in stock at the moment which sure wouldn't fit...and costs $ARM$LEG ...
Ah here might be an option. https://www.jameco.com/z/LM338T-Nati...or_192284.html Would be a pain if it truly was unobtainable, but I'd not be surprised if they become more and more difficult to acquire as time goes by...
I will have to get some it looks like they are becoming obsolete and will be really hard to get
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *
These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%
1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board
All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
The spindle has a separate speed controller board called cheetah-sm-2hp
I was just hooking up a manual potentiometer to control speed...and i connected it per manual.
i know ebay is known for many fake disguised parts but since this machine will only be used once in a while as hobby i was thinking of just buying cheap chinese LM338 off ebay
or is that a bad idea??
i have bought many cheap fake electronic component parts off ebay and have had no issues but most of what i buy goes into items i dont use often
does anyone have first hand experience buying cheap fake parts off ebay straight from china?
If it's just for home use and don't care it prematurely fails, go for it.
Due to its similarity to LM317, I suspect that fakes would be based off this much lesser part. Need to really do testing to ensure you don't have a fake...
what you may find cheap on ebay or ali-express is the older ones that arent lead-free.
those cant be comercially used in most country's so surplus isnt worth much.
yeah im sure they are fakes and not to specs but since its just home hobby use and i wont use it often ill just buy a 10pack of LM338T fakes/non spec for $3 shipped lol straight from china
in no hurry
on the other hand when i bought my sanyo stk amplifier chips i bought from a guy who had 25year old stock..real..all the stk amplifier chips that say sanyo on them now are fakes since sanyo is not a company anymore nor has it been for many many years....sanyo is just a name that chinese bought and market as crap products today...when sanyo was a company they made decent products...this is same with polaroid..zenith..rca..bell howell...these are not actual companies anymore ..just names bought by chinese and put on POS products.
you can tell by the weight and the type of print on the front...i wanted real becasue i wanted to keep my classic fisher receiver original
Comment