Seem it's way to go good old way, if want something done - do it by youself
![Cheesy :D](https://www.eevblog.com/forum/Smileys/default/cheesy.gif)
Will try some usual "try put some parts and see what happens" way later.
For now teardown, as whole internet don't have a single hi-res photo of 4263B internals...
So here we goes, all photos click-able for hi-res.
Front panel
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_front.jpg)
Back I/O
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_back.jpg)
Unit is not deep, but wider than usual Keithley/HP bench meters, so it will not match in rack as for size
![Sad :(](https://www.eevblog.com/forum/Smileys/default/sad.gif)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_side.jpg)
Remove cover by two screws from rear:
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_teardown.jpg)
Bird's view
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_overall.jpg)
Disassembly pretty simple and user friendly. All can be done in few minutes. Well thought design layout.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_front_assy.jpg)
Input BNC connectors.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_inputs.jpg)
LCD is standard 40x2 char type, with very well known 44780 controller. Maybe later I'll change LCD to something with better contrast, if repair will be successful.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_lcd.jpg)
Protection on inputs?
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_input.jpg)
Mains protection and filters.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_mains_filt.jpg)
Unit low voltage power supply in it's cage. Two 22000uF 25V KMH capacitors and lot of small 22uF 50V electrolytes.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_psu.jpg)
Here goes digital board, mounted on standoffs above signal acquisition bottom board. MC68HC000FN10 CPU, two Sony branded CXK581000AM 70ns SRAMs, Xicor X28C64 ROM, AM27C2048 UV ROM with firmware (04263-85041 on my unit) and some big National Semi S9652AB SCX6B65AHI ASIC, and bunch of 7400 series logic and AMD-branded PALs around.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_asic.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_cpu.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_digital.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_dig_pcb.jpg)
No batteries to store cal/configuration constants or NVRAM, only supercap there. So this unit pretty safe from dying from dead batteries, like some other gear
![Smiley :)](https://www.eevblog.com/forum/Smileys/default/smiley.gif)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_prom.jpg)
Some sections done with PCB-PCB modules, one of which near standoff had burnt resistors and SOT-23 resistor.
It's similar to other presumably alive module, so should be not very hard to find out what it does.
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_modules.jpg)
Good module:
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_pnp_npn.jpg)
It have PNP and NPN with small heatsinks on another side.
Input terminals protection and switching. Probably some stuff is borked here...
I already put some resistors to check basic functions, but it's not working right, readings sometimes, all over the joint often, sometimes seem ok.. Need debugging
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_in.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_in2.jpg)
Analog/switching/measurement components
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_ana1.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_ana2.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_ana3.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_ana4.jpg)
![](http://dev.xdevs.com/projects/hp4263b/repository/raw/photos/small/4263b_ana5.jpg)