Another Panasonic HHC

Tony Duell ard at
Wed Mar 22 18:25:12 CST 2006

A couple of weeks ago I mentioned I'd bought a Panasonic RL-H1400 
handheld computer with printer/cassette interface. I've now got a second one.

This one also came with a printer, but also with something labelled 
'EPROM Extender' This is a tray that the computer fits into one side of, 
and the printer into the other side. Underneath there's a PCB with 8 
EPROM sockets.

The plastic housing was glued together, but I've got it apart without too 
much damage. The PCB also contains 10 or so TTL chips (all 
pin-through-hole), a voltage regulator, etc. I've not worked out the 
details yet.

One odd thing is that these EPROM sockets, while the type that take 
EPROMs in plastic carriers (i.e. they're not normal DIL sockets), are 28 
pin, not the 24 pins ones in the HHC itself.

Is this the unit that would take the SNAP development ROMs?

I also have the dual-voltage (110V/240V) mains adapter (my first machine 
came with the 110V-only version). This thing (for all it has 2 fuses 
inside. in nice little holders) is a royal pain to dismantle. It's 
assembled with 4 system-zero tamperproof screws (designed to be 
impossible to remove without the right tool), down holes too small to 
take the right tool. I ended up drilling out the holes slightly (8mm I 
think), then using the system-zero driver to get the screws out. 

It appears (but don't blame me too much if I'm wrong) that the HHC 
doesn't use the NiCd pack as a shunt regulator, there's a proper 
regulator circuit on the logic PCB. In which case it should be safe to 
connect the adapter with the NiCd removed or defective.


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