Here is a comparison, current measurements and a presentation of the interiors of the two displays - the first is the older LCD 8" TV Tevision MD30108K offering antenna and AV input, and the second is the slightly newer EM713/SX-LCD-7CAL 7" 1024x600 IPS/PLS, already compatible with VGA, HDMI and powered by USB. I will check both units with, among other things, an analogue surveillance camera. I will also consider the second unit for use with a Raspberry Pi or other microcomputer.
Let's start with the older hardware. It already supports DVB-T/MPEG2 and runs on 12 volts:
In addition to the remote control, the kit comes with a lighter socket cable that allows you to run the whole thing in your car. The equipment itself is quite handy for its time and has a foot on the back which can also be used as a handle.
These were not yet the days when manufacturers tried to reduce the number of buttons on the case to a minimum, so controlling the whole thing is quite intuitive:
The unit searches for channels - with poor results, DVB-T2/HEVC would be needed these days:
You can only play with the menu, which in my opinion still holds that older CRT TV vibe. That colour scheme and font.
It remains to do a test with a PAL camera - worse that I don't have an RCA to BNC adapter, but somehow one has to manage:
The camcorder works - you know how with the image, after all it is PAL, but it does its job:
I also measured the current at 12 volts:
11.8 V * 1.32 A gives approximately 13.5 W.
It remained to look inside. The copper shielding hides quite a lot from us, but at least by the pulse transformer board and the characteristic connector we can judge that the backlighting here is still fluorescent. The whole circuit is not yet as integrated as in newer monitors.
Of the separate circuits inside, the LN386N amplifiers and the PT2259 driver are conspicuous, the rest I have not analysed.
Finally, the instructions:
Roughly speaking, the market value of such used equipment is £50-100.
LCD EM713
Now a newer equivalent - LCD EM713 , also branded as Surix SX-LCD-7CAL. Price around from $33 from China, for Polish it's £120.
We start with the contents of the kit, as the box was unlabelled. This is also where we get the wires to start.
Image is quite legible, no problem looking at an angle:
The monitor accepts a 1920x1080 signal which then goes to a 1024x600 matrix:
The menu is already reminiscent of the style of newer designs, we have here the basic picture settings, but the Polish language is not to be found anyway:
The monitor does not introduce noticeable delays:
We received an RCA to BNC adapter in the kit, so there is no problem connecting the camera:
Now the current measurements. The backlight setting changes the current a lot, brightness not at all. First backlight 10% (you can go down to 0%, but that's pointless - you can't see anything then and there might be a problem with the backlight):
5.1 V * 0.35 A = 1.8 W
80%:
5.1 V * 0.68 A = 3.5 W
5.12 V * 0.84 A = 4.3 W
In summary, such a monitor costs us between 1.8 W (with a lower backlight it is unlikely to be usable) and 4.5 W.
It remains to look inside:
Date on the matrix - 2025-06-27, fresh.
Everything is on a single PCB. The heart of the chip is RTD2660H , a well-known chip, also found in universal LVDS controllers.
Right next to it we see the 25VQ40BT, a Flash memory, and the ET4334M, a 24-bit DAC converter. This appears to be for audio. There are even smaller chips - two T50Af62s, anyone decipher? It seems to me that these could be separate right and left channel audio paths.
The two HAA2018s at the connector from the speakers need no explanation - they are audio amplifiers.
Summary
This was a brief comparison of the two displays. I realise that they are not de facto the same thing, but I was tempted to put them together in this topic anyway. I was simply replacing the unit at someone's house and had the opportunity, both of them to play with each other for a day.
The results speak for themselves - in terms of power, it makes no sense at all to keep the older unit. This is due, among other things, to the replacement of the older fluorescent backlight type with a more efficient LED backlight. 13.5 W versus 4.3 W is a threefold difference, although it is still worth considering how much and for what we use the screen - because if we turn it on occasionally, I doubt it will pay off.
Although it's fair to point out here - the newer one was a 7-inch unit, and the older one was an 'eight'. Well, but that alone won't explain the big difference, of course.
Another thing is that the older one doesn't have HDMI or VGA at all, but that's rather obvious at first glance. In many applications, this makes it useless.
I guess that's it - and do you guys use these types of smaller monitors, and if so, for what? Raspberry? A camera? Something else?
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