Anyone installed LCD panel for HP8591EM? - Page 1
Forum section: electronics / testgear

author: tkamiya
author_rank: Super Contributor
timestamp: April 08, 2018, 02:36:00 pm
content: There is nothing wrong with a display of HP8591EM that I have.... But I'd love to replace this CRT with LED type. Looking through "the net", I can't seem to find any example of anyone doing it or a product to do so. Apparently, EM uses a different display module from rest of the 859x xx line? Something about scanning frequency different.Has anyone here attempted this?

author: EE-digger
author_rank: Frequent Contributor
timestamp: April 08, 2018, 06:53:55 pm
content: I have an 8596E. Other than EMC related bandwidths, Quasi Peak, etc. I don't think there should be a difference in display, but could be all wet. Your best bet may be to ask the NewScope (on Ebay) or other (Custom-Cal.com, others).Looking at the one on Ebay, and having done several Tek TDS7xx, 6xx scope conversions, I don't see any vertical artifacts, just smooth curves on the rising waveform. But then again, you're not dealing with sharp edges (which cause the 1 pixel horizontal steps in a vertical line that is fairly steep). In time domain you may see them but otherwise, these look quite niceadded - I seem to recall that these analyzers do have a composite video that is not quite NTSC. I think horizontal may be off a bit. Not all composite monitors were happy with the signal.

author: TheSteve
author_rank: Unknown
timestamp: April 08, 2018, 07:04:01 pm
content: Do you have the specifics of what video format it uses. I have experimented with converting the video from an HP 8920B service monitor to VGA for an LCD and just finished the conversion of an HP 8752C network analyzer to LCD using cheap parts that are easy to get.

author: EE-digger
author_rank: Frequent Contributor
timestamp: April 08, 2018, 08:01:08 pm
content: As I thought, from page 2-7 of the 8591 EM user guide ..."10 - MONITOR OUTPUT drives an external monitor with a signalthat has a 15.7 kHz horizontal synchronizing rate. I t can also beswitched to provide an NTSC format output which is compatiblewith VHS video recorders or a PAL format which is compatiblewith PAL/SECAM video recorders."You could use any LCD of appropriate scaling for the soft keys, and a good range of adjustments. Many of the cheap Chinese display / VGA input modules will work or not work because they lack some variety in adjustments. I've used a very nice controller board made by Digital View. Around 4 years ago, the board was around $150. Used my own choice of panel. Digital View has cables supporting various name brand display panels.

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2018, 09:48:05 pm
content: Why would you want to replace a perfectly good CRT with a cruddy LCD? That's the sort of swap you do when the CRT is worn out and you can't find a replacement, it never looks as good IMO but it can get the job done.

author: tkamiya
author_rank: Super Contributor
timestamp: April 10, 2018, 02:28:57 am
content: I used to have an "E" and tried the external output. It didn't look good enough even for a casual use. Color-shift all over the place ala Apple II on a composite color display.Why? I'd like to lighten it a bit. I have some back issues. I thought if it can be done, it'd lighten the weight. Besides, contrast is much higher and easier to see for me on LCD than CRT.No, I'm sorry, I don't have ANY specs on what's inside. It being different, I'm just quoting a service tech who told me this.

author: gregariz
author_rank: Frequent Contributor
timestamp: April 10, 2018, 03:40:54 am
content: Quote from: tkamiya on April 08, 2018, 02:36:00 pmIf memory serves, (and its not good btw according to my doctor) most modern / not so modern monitors had trouble syncing down to 15KHz, because they were not designed for interlaced signals. This was a common problem on some of the old computers ie Amiga designed for use with televisions. The fix was a scan doubler that de-interlaced the signal and pushed it up to 30 odd KHz. Recently I dragged out my old TRS-80 and found I had a similar problem. I ended up first doing a composite conversion (by modifying the RF modulator box) and then by buying a video to HDMI converter box. As luck would have it, it was able to sync to it and the HDMI into a modern monitor looks good.

author: TheSteve
author_rank: Unknown
timestamp: April 10, 2018, 03:49:31 am
content: If you feel like experimenting order a GBS-8200 from ebay and buy an LM1881 sync separator. You can feed the external video into the GBS-8200 RGB inputs and also into the LM1881 which will generate composite sync to feed into the GBS-8200. This will give you VGA out. Once you get a signal you're happy with you can find a suitable LCD with a VGA driver board and then fit it all into the 8591.The GBS-8200 should be under $20 shipped and the LM1881 should be a few dollars.