TBC-4000 discoloration on chips?

[bigkazzyry]

I managed to acquire two TBC-4000's and they both work, pass clean signal on all channels. Initially I thought I had an issue with two of the channels on one of the units which is the reason I decided to open them up. As you can see, it appears that the two units have different chipsets. One is very clean and is conexant and the other has a haze/discoloration across the chips and the manufacturer can't be made out but is noticeably different.

On the unit with the discolored chips I decided to pull the top TBC-3000 board off to inspect it further; the bottom TBC-3000 board has the same discoloration. I tried to clean the chips off with 91% alcohol and the haze returns.

Any thoughts on the discoloration? My initial thoughts were that they overheated but it could be the difference in manufacturer and the age of the TBC.

Any thoughts on adding some heatsinks to the chips to ensure they stay cool since the TBC does function as expected?


Thanks,

[hodgey]

I think this is intentinal sanding of the chip markings done by the manufacturer to conceal the hardware for whatever reason. My TBC-3000 also has video A/D, D/A and (what I assume is) FPGA chips markings sanded. Though on yours it seems to have been done a bit more lightly.

The Conexant chips in the zoomed picture is a BT-BT865.PDF video encoder which converts the digital signal back to analog. The sanded on from the other board looks like it has a Bt (Brooktree) logo. The company was bought out by what later became conexant, so it makes sense that the chips may have changed from brooktree to conexant at some point.

I don't have a picture of mine here right now, but it looks similar to this one.

I'm still curious to what other chips (A/D converter and FPGA?) datavideo used in their TBCs. The pictures I've seen have all been to low-res to make out what they are and on mine they are sanded as mentioned.

I've thought about adding heatsinks myself. I've found that the TBC very occasionally can output a messed up frame (there is a forum post somewhere from someone else with that issue but I can't find it.) so I've wondered if it could be overheating related.

Overheating does seem to be an issue on the Black AVT-8710 TBC we got, I think it's the FPGA chip in that case, but not really using that as it's one of the newer borked ones anyhow.

[lordsmurf]

The 4000 are double stacked 3000 boards. Your top boards appear to be 3rd and 4th gen, but not 100% sure. There are tell-tale signs in performance, offset, and noise, not just visual difference, in determining generation. The gens also behave differently for PAL and NTSC. No TBC is 100% perfectly transparent, though that is the goal for quality TBCs.

Again, the 4000 boards are 2x 3000 boards. If you had another TBC case, you could pull apart the 4000s to make 2x 3000s. DIPs 3 or 4 control the button behavior between 3000 mode and 4000 mode.

As far as heatsinks, not sure it's possible for the bottom board, not much clearance. I've never added any to mine. The chips get extremely hot, but do not self-fry like Cypress chips do. The metal body case probably absorbs much of the heat.

Chip sanding was a practice used by many manufactures to obscure components, make reverse engineering more tedious for competitors, would-be competitors, and DIYers. This is still done even today.

Nice find. Where from?

[bigkazzyry]

Great information on the reasoning for the chip being discolored and why they might have done that. It had me a bit worried at first. I'm curious on others thoughts on the heat sinks. The only concern I came up with would be the heat from the bottom tbc-3000 board rising directly into the top board. I'm a novice so I'm curious on what some of the experts think. It seems to work for Raspberry Pi's and depending on the model and case is required.

I found the pair from a guy on Craigslist. He was trying to sell his whole video studio as a package but I spotted he had posted these separate and asked about them. Unbelievably I got the pair for $401 shipped. Lordsmurf, if I decide to sell one of them what kind of price would it pull? I'm considering it to use the funds to return my AG1980's with Tgrant.