asked Oct 23, 2009 at 5:29am
Hp HP LaserJet 4

HP4 50 Service message

I am receiving this message after warm up. I have followed the instructions and checked the fuser. I found 3 ohms on the right and .5 ohms between the lower two pins on the left. Everything else is open. Before I spend money on a power supply, is there any way to further troubleshoot to see if the problem lies with the DC controller or the power supply?
Also, I noticed after the warmup cycle, I hear a faint click and then I get the 50 service warning.
Thanks for providing this service. It is really helpful.
There is know other way of trouble shooting this problem.As these printers age, power supplies are becoming more common as the cause of 50 Service Errors.So replace the power supply should help your problem.
by unknown on Oct 23, 2009 at 7:14am Add comment
OK, thanks Shawn. I thought I saw a repair kit here for one on them.
by JoeP on Oct 23, 2009 at 7:29am Add comment
If you need a power supply, click on my name for pricing/ordering info.
by moe on Oct 23, 2009 at 8:05am Add comment
just a note: very cool you're still using the laserjet 4. they'll run forever with very basic maintenance.

the earth thanks you...
by chris on Oct 23, 2009 at 11:21am Add comment
OK, I replaced the Power supply and am still getting the 50 Service message. I presume the next step is the DC Controller? How do I get one and how difficult is it to replace? So far everything about this unit has been very easy to service. Anyone need a good Power Supply?
by JoeP on Nov 3, 2009 at 9:06am Add comment
OK, I was able to resolve my HP-4 50 Service error problem and wanted to let you know how it came out. First I bought a service manual from an Ebay supplier for $5. Here is the item # for anyone else that wants one - #290339076227. You can download it from the guy's website once you buy it now.
With that in hand and a DC controller found through another e-bay search, I was able to remove and replace my DC controller. It now works again - YAY!!!
I couldn't have done it without this great site. Thank you Moe and everyone that works with you for providing this great service. You will be in my bookmarks now forever.
by JoeP on Nov 13, 2009 at 3:08pm Add comment
You could have checked the manual section of this site, where they are always free.
by moe on Nov 13, 2009 at 4:21pm Add comment