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LaserWriter IINT flashing no paper, now flashing both no paper and jam

pezter22

Well-known member
Last year I bought a Mac II and the owner gave me a LaserWriter IINT that had been sitting for decades in his basement. It's very clean, just dusty.

I bought a LaserWriter IIg controller board and recapped it and installed it in the printer. At first I got a no paper flashing light with the cassette installed. I cleaned area and sprayed Deoxit on the contacts.

When I turn it on, I hear the motor engage and the paper cassette clunk. However, now I get both the no paper and jam lights flashing. I reinstalled the old NT controller board and get the same error.

I am guessing an issue with the Distribution PCA and either the paper pickup solenoid or the paper out sensor. I will be opening up the printer to gain access to the PCA later today.

Any other suggestions would be greatly appreciated.
 

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pezter22

Well-known member
I'm guessing recapping the power supply(s) next.
I found this great old Apple Service Training video
 

NJRoadfan

Well-known member
Two red flashing lights is either a power supply problem or a fuser problem on these. Both are very common issues on SX engine printers. Equivalent to HP LaserJet II's ERROR 50. Used to be that both parts were easily sourced and swapped out, but that likely isn't the case anymore.
 

ScutBoy

Well-known member
Very likely a bad power supply block. Not hard to replace. It's the same part as used in HP Laserjets of the period. My old notes say these are the suitable part numbers. Of course, you can recap/repair the one you have.

RG9-0205
RG9-0319
HP SX-ACPM-B
 

pezter22

Well-known member
Thanks for the suggestions. I have replaced the AC Power block and recapped the daughter board with the green 22uf leaky capacitor. I have also recapped the DC Power Supply, the High Voltage power supply, The DC Controller PCA and the IIg Controller Board.

I was able to get the two red lights (Paper Jam and No Paper) to go away. When I turn on the printer, I get a steady green light, but I do not get a test print. My Mac SE sees the printer and I can attempt to print a file, there is communication with the printer and it appears to complete, but nothing comes out of the printer.

The fuser never gets hot.

I have found is I am not getting 24v anywhere on the printer. 24v is needed to power and heat up the fuser, turn on the fan and the motor. I am only getting .5v on the areas that should be 24v. I do get the other proper voltages like 5v and 1.8v throughout the printer.

From what I understand with the schematics is 24v is generated with the Top Cover Interlock switch is pressed on the DC Power Supply. When the lid is closed a tab presses the switch on the DC Power Supply.

When I checked the Interlock switch on the DC Power Supply, I was getting random ohms readings, nothing consistent even when I pressed the switch. I do get a continuity on pin 14 when the switch is pressed on the DC Power Supply connector that is plugged into the DC Controller PCA. So there is a connection, just not a signal.

I ordered replacement switch from Digikey and it should arrive later this week just to see if that may give me the 24v. If not I will buy a replacement DC Power Supply.
 

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pezter22

Well-known member
I installed the Top Cover Interlock switch today on the DC Power Supply and I am still missing the 24v power circuit. Tomorrow I will install a new Triac on the AC Power block. I am reading good steady 80 ohms. On my other AC Power block I was getting random readings.

Thankfully parts are still available. I found a DC Power Supply and a Fuser Assembly and will replace them. But I can't keep throwing parts into this either.

I just find it frustrating not being able to find why it's not generating the needed 24v to the Fuser Assembly. It does plug directly into the AC Power block, which I am hoping replacing the Triac will work...

This thing sat for three decades, it will have to sit for a while longer.
 

joeventura

Active member
I installed the Top Cover Interlock switch today on the DC Power Supply and I am still missing the 24v power circuit. Tomorrow I will install a new Triac on the AC Power block. I am reading good steady 80 ohms. On my other AC Power block I was getting random readings.

Thankfully parts are still available. I found a DC Power Supply and a Fuser Assembly and will replace them. But I can't keep throwing parts into this either.

I just find it frustrating not being able to find why it's not generating the needed 24v to the Fuser Assembly. It does plug directly into the AC Power block, which I am hoping replacing the Triac will work...

This thing sat for three decades, it will have to sit for a while longer.
Besides the DC power supply I have a spare of most every part in that printer (all work) so if you need stuff let me know and for the cost of freight I can send you a care package and you just send back what you don't need.

I know I have:
AC Power block
AC Fan
HV Power supply
I think I have a fuser
The optical scanner
etc

Ill bbe out of town until Monday, let me know what you need and I will try and help.
 

pezter22

Well-known member
Progress today. I have a steady green light.

Previously I wasn't getting 24v anywhere on the printer. I 68kmla member Joe Ventura provided me with a replacement AC Power Block and I purchased a replacement DC Power Supply and the printer finally woke up.

On startup the printer attempted to print a startup page but gave me a paper jam error.

I watched the Page Feed Roller and it only made a quarter turn, then stopped and the paper jam error light came on.

I listened and watched the Paper Pickup solenoid (SL302) on the Paper Control PCA, it clicked and the roller began to move, a second later it clicked again and the roller stopped. No other movement occurred.

I purchased a replacement Page Feed Roller and a Paper Control PCA from eBay. They arrive on Monday. Hopefully I can resurrect this neglected printer going again.

I am glad I have gotten this far.
 

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