www.shaneburrell.com BLOG Search – Rescue – Scuba – Diving – Telecom – Electronics – HAM Radio

25Apr/120

HP 8935 E6380A EL Display Fix

I have a HP 8935 E6380A service monitor that had some pretty severe screen burn.  After looking around for a replacement I wanted to see how hard it would be to adapt a current LCD to the 8935.  Suprisingly it was fairly easy.  I had a 10.5 inch display and after probing around a bit to see what signals/power were on the A1A1 connector (400 i think) I started playing with a FPGA dev board to convert signals to something I could see on the screen.  It works but doesn't fill the entire screen and its not the right size hardware.  Now that I have a PLAN B and I've found a 6.5"ish lcd I can readily buy cheap, I'll troll along with the burnt display till it fails or I can't stand it anymore. I'm hoping there is a lot of interest in this to other 8935 owners and its something I can justify doing in the near future.

Some things I played with while I had the 8935 apart and the 10.5" connected:

- Inversion to have some way of preventing screen burn.

- Adding some color (Changed boarder color, changed color of spectrum analyzer portions of the screen) This isn't something that can be done everywhere. If its simply which pixels get what color it's trivial.

- Added text to the parts of the screen not used going from 512x256 to 640x480.  Could add ADC to show voltages etc as extra info.

-Centered screen and added border.

 

23Apr/120

B & K E200D Issue and the Fix.

I recently discovered my B & K E200D would no longer modulate while working on a Kenwood TS-440AT.  After getting inside the E200D nothing appeared to be unusual and I remember a site I had used before when searching for the switchcraft connector I needed to make a cable for this unit.  http://www.freeinfostuff.com/E200D/E-200D.htm .  After going thru the calibration procedure, everything was in calibration with the exception of the modulation level which once I adjusted the level the modulation meter was back in action.  Easy quick fix and now I know that the unit is calibrated.

3Aug/116

Tempo 2020 Henry Uniden HF Radio Project.

I recently purchased this Tempo 2020 HF radio to rebuild.  I plan to start this project after the TS-430S is finished.

I've been scouring the net looking for information about this radio. Below are some links I've found thus far.

Yahoo Tempo Group (Very Useful)  http://groups.yahoo.com/group/TEMPO_2020/

KX4OM Tempo 2020 Repair pages  http://www.kx4om.com/TechSolutions/Tempo2020_repairs/2020.html

28Jul/110

B&K E-200D and Heathkit Signal Generator Cable Connectors

I've had several email's about some of my test gear in recent weeks and one item of interest from many was the cable used on my B&K E-200D Signal Generator.  I used a premade 50 ohm BNC cable and attached a 2501F connector.  So if you need these connectors they can be found numerous places.  Search for 2501F, vintage mic connector etc to locate the connector.  I prefer when possible to keep my gear original in case I sell the unit for an upgrade and the cost of the connectors is very small. I was able to purchase two for less than $12 including shipping. On is a BNC adapter and I used the other for a 50ohm gator clip style cable.  Switchcraft is the manufacture of the connectors I used.

 

The datasheet is below.

Switchcraft Vintage Microphone Connector

 

 

 

23Jul/112

Kenwood TS-430S Filter Unit Board Repair LPF

I've been doing some clean up on the filter unit for the Kenwood TS-430S HF radio.  Some bands were not working and the filter unit was suspect.  I had already tried the prescribed 12 V DC current treatment without any changes on the bands that weren't working.  I noticed several bad joints and manually disassembled each relay and checked its operation. At least two of them were not making good connections and required cleaning with some contact cleaner and a dollar bill.  After this cleaning they seem to be working.  I also noticed several bad solder joints. Here is some photos of the board.

 

20Jul/110

Kenwood TS-430S Clicking on Transmit Problem TX

After doing some initial testing on the Kenwood TS-430S project cleaning up the IF board issues I had been getting 100 watts on some of the bands.  Suddenly last night during a test I noticed the radio would begin clicking and resetting.  After a bit of head scratching and doublechecking power going into the radio I finally traced it down.  The molex connector at the rear wasn't making a good connection.  I used some needle nose pliers and some deoxit and solved the problem.  A quick fix to a problem is always good.

 

14Jul/110

Kenwood TS-430S IF Board Repair

07/14/2011 - After removing the IF board from the TS-430 I could see some issues right off hand.  The top site of the board was realitivly clean although I noticed some excess thermal compound on the regulators which gave me a hint that this IF board had been repaired at some point.  Getting it out I could see lots of oxidation, burn traces at one of the regulators and at least one connect that had ripped the traces from the board.  Tonight I cleaned up much of the board tested all the diodes on the rear of the board, and repaired the 5V traces.   At this point the radio seems to work but I don't have very good recieve and it still only transmits on some bands.  On the bands it does transmit on it does full output which is a good sign.  I'll be working on the IF board for the next few days as its in bad shape on the rear side.

07/18/2011 - Well thus far, I have replaced the traces on the 5V regulator with jumpers as the eyelets were missing and that area of the board wasn't in very good shape.  I also located a burnt or gouged trace which will need repair.  A missing eyelet was found on Connector 10 and I ended up glueing the connector to the board and replacing the trace with a wire.  After looking at the board from the top I've noticed several missing caps.  I expect someone has tried to repair this board and during checking cold solder joints they may of pushed the caps off the board without noticing.

07/19/2011 The gouged trace has been repaired.  Now the IF section seems to be working at least a stage or two away from the audio section.  I ended up with a TX issue which was a bad connection at the molex connector which slowed progress on the IF board issues.

 

 

 

 

2May/1130

OSW 1.0D Kit TM-D710A keyboard adapter.

05/02/2011  07:12 AM - The order for the 1.0D board has been processed and passed design checks with manufacture.  We all should see boards from the group buy in the next 3-4 weeks hopefully.  Parts have already arrived.  I'll be posting more information and documentation during those long 3-4 weeks of waiting here.  I recommend to everyone to use an AVR platform for MCU development an interface but you are welcome to use what you want.  The goal is to end up with something that is under the 100ma current of the MIC interface. Read more...

2Nov/100

APRS TNC using Arduino with a display.

Several folks have asked about using Arduinio hardware with APRS TNC.  I don't have a lot of motivation but figured I'd get the project started.  If you have an arduinio and would like to help develop this using arduino hardware please post (no emails please).  Here is the alpha schematic I'm working on using the display I started with in the original design.

Arduino TNC Shield

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21Oct/100

APRS AVR C vs Processing (Arduino)

I've gotten ton's of emails (100 or so) about the code for the APRS node I've been hacking away at.  I normally use an Arduino type board for prototyping.  However, the code is in C.  I do sometimes use processing to quick test something but generally things destined for the embedded world are in C.  Below are some projects I found related to what I am working on.  Some use the CML chips some don't. In the low cost model I don't use it.  I have been playing with a CML chip for digital type radios but they drive the cost up with what I am attempting to do which is build a device within the reach of just about any public safety department in volume.  And please if you don't mind, post questions as comments rather than emailing me directly.  That ensures that any Q&A can be seen by everyone.

http://garydion.com/projects/whereavr/   - This is a really nice setup, different application but very tidy setup.

http://sites.google.com/site/ki4mcw/Home/arduino-tnc - Hope to see more from this.  Its what more of you are looking for with PDE files provided.