Powerbook 2400c with GLOD

[Alex]

Hello folks

I have two 2400c's. One of them has GLOD. The speaker clicks when I attach power and no screen. Up to now I have done the following, taken it apart, added a brand new battery and a brand new hard drive. I put it back together and no change, just GLOD and a single click from the speaker. No surprise there I guess. I checked all the fuses on the power board and all have continuity. I don't know where to go from here. I don't know enough about electronics troubleshooting to measure voltage which is where I think I have to go next, to understand where power is going or not going when it should. Can someone with more experience chime in and give me some starting points and a quick overview of how to check the power board for voltages? Maybe a video or a document? The adapter does work as it powers the other powerbook correctly.

Any advice is welcome. I will leave it here for now but if you need more info let me know, I can pull out the machine which is in pieces now in antistatic bags and provide photos if needed. Unfortunately schematics are no where to be found, at least I can't locate any. Thanks in advance!

 

[beachycove]

A 2400c, probably more than any other classic Apple machine, needs a functional backup battery. By adding a "brand new battery," do you mean that you replaced the main battery or the backup battery?

 

[Alex]

Thanks for the reply. I have a working removal battery that I tried and the internal PRAM battery has been rebuilt and I can confirm that it works as expected. So to answer your question, both batteries are working.

 

[Byrd]

Are you sure you've checked all the SMT fuses - IIRC there are 5-6 fuses on the 2400c motherboard, which is the main cause of GLOD on the machine.

 

[Alex]

there are 5-6 fuses on the 2400c motherboard

Hi Byrd

I can't say with all honesty that I checked the motherboard for fuses. I didn't realize the MOBO had fuses. I know I checked the power board fuses several times and there is continuity. I will have to go back and check the MOBO in a few days. The last time I checked the machine was about 2-3 months ago when I had rebuilt the internal PRAM battery. I will check the fuses on the MOBO and then report back. I will provide a detailed report on all fuses checked so that it is here on the record. Thank you for letting me know!

In the meantime, just a quick question, are there schematics anywhere around? This machine has virtually no documentation to be found.

 

[Byrd]

Hi Alex,

the lowendmac Duo mailing list (assume to find on internet archive) is where I found info about all the SMT motherboard fuses. I haven’t pulled my 2400c apart for years, but recall they are little white squares 5-6 all scattered throughout the board. Also, remember to use the power adapter to suit an iBook/PowerBook G3, not the “Duo” brick as it will kill the fuses. I learnt this the hard way!

JB

 

[bibilit]

[No message]

 

[Alex]

Thanks for reminding me of my own post. Oh my goodness, I forgot about that. I will review my own post and @Byrd thank you for the cautionary note. I have the bonafide Apple 2400C adapter so of course I will use that. Thank you both!