[time-nuts] OT - Tek 7L18 ROM

[Dave Baxter]

If no one else has said this.

Check the mainframe power supplies.  The 7L18 is a thirsty beast.

If anyone can back up the rom images, well done.  It's one of the
"classic" machines internally driven by the "Original" microprocessor,
the Intel 4004!  The Rom's will be of a similar vintage, multi rail
supplies etc I suspect.

(I've only ever seen one other instrument that used a i4004 CPU, a
Finnegan GC oven!)

As below, get on the TekScopes list for more info.
TekScopes at yahoogroups.com  is the one to go for.

Someone has also started a Microwave equipment group too.
http://groups.yahoo.com/group/MicroWaveandTestEquipTrader/

Again, you need to subscribe to even see the messages, a spam reduction
precaution, sadly.


Regards.

Dave B.
An ex Tek(UK) employee, who used to work on 7Lxx's in the past.


---- Original Message ----

>Hello all,
>I have an old 7L18 spectrum analyzer that used to serve me well on the 
>higher bands.
>Unfortunately, the controls have got into complete disorder.
>It seems like one or both of the ROM's are dead.

>Anyone have / knows where to find ROM images of the 7L18?

Adrian
Can I suggest you post this to the tekscopes group - they have answers
to pretty well everything Tek Having said that I do not know of any ROM
images out there - I have 2 7L18s but have never got around to making
ROM backups - never been able to find the ROMs to burn.

Assuming it is the digital section at fault (eg no panel controllable
frequency on the readout display)Several pointers;
1) If not used for a long time, the connectors, both internal and to the
mainframe can go very dirty.  The PI uses lots of power & needs every
connector to be doing its job.  Some users say remove & slam in the PI
several times to help wake it up (very brave/stupid ones do it with
power on)
2) digital parts can be affected by gone bad electrolytics pulling down
the supplies or eg: affecting the processor reset circuit.
3) in my case the processor board had a defective RAM - no response to
controls because no boot, although it would get to different stages of
the boot process before halting.  (Got a replacement chip from that
auction house)
4) because the various sub sections/boards are so interconnected the
best way to trouble shoot is to have a 2nd 7L18 (or at least a second
processor board)available for board substitution.
5) you can make extenders which allow board level trouble shooting - the
digital bit runs quite slowly and a logic analyzer will help if the
problem lies further down the line.
6) finally, if you can back up the ROMs, I would like to place an order
for a set!

Chris HJ