Thandar TG2001

[Hydrocarz]

I'm baffled! I thought it would be some sorta Clocking circuit in this unit, It uses a flip flop MC10H131 to generate the signal I guess, and it starts out using op amps to alter the voltages. I've got to the point to where I know most of the circuits is not in the files I was given by the website. I'm not familure with how the flip flop is triggered so theres not much I can do to fix it. It is very dissapointing I cant figure this out. I'm just not sure how these flip flops are triggered, If I was I would be inspecting the control areas. I just dont know where to look. I will keep on studying this circuit, i'm somewhat irratated because i've burned a trace from the board, and also its difficult to obtain these parts. I salvaged a few parts from another working unit that had flaws but I have gotton nowhere. I think theres 30 transistors total on the board, not including the Digital Logic ones. Also, the ones I have that work, everything in them just about generates a ton of heat. I cant understand how something can operate at such great temperatures, but thats just the way its designed.


I guess you could call it a voltage controlled Comparator that controls a dual flip flop? Perhaps a Schmitt trigger?

If I could understand the flip flop and what triggered it id stand a much greater chance.

[Hydrocarz]

I believe I found whats inside that flip flop of the MECL family.. Now I understand a little bit more about why so many of those op amps were used, and I can understand that their method of using a Bilateral switch is basically a motorola scheme... If I didn't know any better id say someone from Motorola designed this gen..

[Radio Wrangler]

The 10KH family is emitter coupled logic as can be seen in the diagram of a basic gate you've posted. The flip flop is made up of a number of gates made of this technology in a feedback arrangement.

Each chip contains two D-type master-slave flip flops.

A master slave flip flop is really a pair, one after the other. One is clocked on the rising edge of the clock pulse, the other on the falling edge. Pulsing the clock samples the data on the D input pin, and stores it, outputting it on the Q pin, and also outputting its complement on the Q bar pin.

These flip flops also have asynchronous set and reset inputs which can be used to force the state of the flip flop at any time.

So your 10H131 can be triggered to change state either by pulsing the clock input, when it will sample and hold the data on the D pin.

OR it can have its state changed by activity on the set and reset pins.

OR it can use a mixture of the above.

ECL logic is both expensive and power-hungry, so designers use every trick they know to minimise the amount of hardware.

ECL logic swings are only about 800mV between logic 1 and logic 0 levels and neither lavel is near ground.

ECL was originally designed to run from a -5.2v supply and ground. Done this way, the logic levels are fairly well defined with respect to ground and they are less noisy and less dependent on really good power supply decoupling.

But TTL and its +5V supplies came to dominate the world, so a lot of people use ECL with what would have been the ground pins at +5v, and what would have been the -5.2V supply pins grounded. It works, but noise margins are not so good and it needs really good decoupling of the +5v supply lines. Also , the logic 1 and 0 levels are up near the supply and will move, tracking the supply voltage. This gets called pseudo-ECL or PECL.

Note that ECL outputs are open emitters and don't work unless you provide an external pull-down resistor. This is to let you choose the value and choose between speed and power consumption.

There are also ECL 'line receiver' parts which can get used as fast comparators and even as analogue amplifiers. There is a huge history of the artful mis-use of these parts.

If you're used to TTL/CMOS logic, then ECL is a whole new and weird world!

David

[Hydrocarz]

If you look at the schematics the website has given me and if you look on the first page it does not appear to be related in any way at all to the Thander TG 2001. I wonder if this was by mistake or if there is a secondary board in which we know nothing about but even the labels in the schematic indicates the IC labeling is much higher than what is in the original schematic. At this time I really have not done that much but I have indicated that the bilateral switches is not in the schematic where they go to the push button switches but I have traced a lead or two down from the bilateral switch in the schematic and it does go to one of the upper ICS which at this time I don't have access but later I will update the forum on this.