TBC-3000 heatsinks installed, questions?
 

I had a bunch of extra Rasberry Pi heatsinks lying around so I figured I'd go ahead and try them out on my TBC-3000 before I go through the trouble of doing this times two with my TBC-4000's. Surprisingly, the fit great. I had no way to get any kind of baseline temp so performance wise I don't know that I'll be able to garner much from the addition of the heat sinks but I figured it would be interesting to do.

Is there any issue with using two small heatsinks to cover the memory chips? I did look for a properly sized heat sink for the memory chips and I couldn't find one that would fit them. These two smaller heatsinks measure out to 17.6mm x 8.8mm. I didn't know if that would cause heat disbursement issues since they aren't single piece heat sinks.

Amateur Question: What is the chip that has the VP-293 V3.4 (8DE3) sticker on it? Does it heat up enough to justify removing the sticker and putting a heatsink on it?

What you see is the main chip, gets hottest.

That is somewhat neat, but I wonder if it's really needed. The bigger issue I see is the TBC-100 (heart of TBC-1000) get massively hot, like 2nd degree burns from touching it for 1s. And the AVT-8710/Cypress chips get hot as well, with the main problem being plastic construction that doesn't absorb heat.

Most likely a ROM chip, I don't think these typically get very hot.

Also a small request, you wouldn't be able to tell us what the A/D chips at the top are on the one(s) that re not sanded?

Thanks,

When I get home I'll take some close up shots of the tbc-4000 that has unsanded chips and post them here.

-- merged --

Attached. TBC-4000 with Unsanded chips. I wasn't sure which chip you were referring to so I attached close-ups of all the main chips on the board.

Thanks a lot!

So it's using a Philips SAA7111A video decoder, one of the chips I was suspecting. Interesting that there's a third SAA7111A at the bottom though, I would have thought it was a FPGA or something. Maybe the big socketed chip may have a bit more than just ROM in it then.

I took this the other day before I put the heatsinks on my TBC-3000. Rather than pull the heatsinks off this might give you something to go on as it looks different than the Phillips chips on my TBC-4000.

In regards to the rom looking chip, that's what I was trying to sort out from Lordsmurfs comment above. Sounded like he was saying that's the main chip that gets severely hot. I supposed I could run the TBC for a while in a capture and get some infrared temp readings to see.

Lordsmurf,
I'm sure it's not necessary as this TBC has been around for a long time without heat sinks. I'm doing more for the fun of tinkering.

Just to clarify, were you saying the chip with the sticker is the main chip and it gets the hottest of all of them? Just want to be sure.

On a side note, the spacing between the tbc-3000 boards in my TBC-4000 is fairly large. I placed a 15mm copper shim on the bottom board and it easily has an addition 3-4mm to spare beyond that. Definitely enough room to put these small sized heatsinks on the bottom board. This is in reference to a comment from the other day when I was asking about the discoloration on the chips of the tbc-4000.

I believe so, but it's been quite a while since I tested the temps on TBCs.

I suspect the big socketed chip is a CPU or MCU that's driving the whole affair. An MCU from the various manufacturers could have a small amount of flash memory embedded to store the device's firmware. Those rectangular chips look like RAM to me. From lordsmurf's description of the devices function, it seems to me that the SAA3111s digitize the input stream, buffer it in the ram chips, and BT865AKs draws the data out and reconstructs the analog frames, now with a stable, steady time base between frames.

I don't suppose you could get photos of the socketed chip and the RAM chips, could you? I'm curious to look up their specs.

TBC-4000-Images of top board (Sanded Chip Board)
 

Okay,
Here are several views of the TBC-4000 (The one that has sanded chips). I included close-ups of a lot of the board and some of the smaller chips as well. Please share any information you find in your research! I'm enjoying learning more about these devices.

Koreth,
I will be adding a heatsink to the main socket chip on my TBC-3000 board very soon. When I do, I'll pull the sticker that is on it and take a picture of that chip as well. I'd be curious if it uses the same main chip.

Okay, it looks like I was right about the socketed chip. Looking up the markings identifies it as a Winbond W78E51 8-bit microcontroller. It has 8KB of onboard flash, and 64KB each of program and data memory (sounds like a Harvard Architecture), per the datasheet that I found [1]

The numbers on the sticker sound like version numbers to me. So, I suspect whats happening here is that the device's firmware is burnt to the flash on that combined MCU/flash chip, and the stickers were part of production to identify which verison of the firmware is present. I've seen this on other electronic devices; the chip containing the firmware, whether an EPROM or flash, will have a sticker with a version number on it, and may or may not be removable, depending on how serviceable the device was intended to be.

I'm still looking up the memory chips. Knowing the details of their type and layout may offer further insight as to the TBC's architecture.

1. https://www.datasheet.live/index.php...W78E52P-40.pdf

The link didn't work in my browser but that's great information. On this particular TBC it had a single, round, yellow sticker applied to the main socket chip. It is my TBC-3000 that has the full size sticker on the socket chip. The other TBC-4000 I have also has a round yellow sticker and appears to be a Winbond chip with a slightly different model number.

The ones you captioned PROC AMP are voltage regulators.

It seems Datavideo may have used different Microcontrollers for the revisions, this TBC-3000 has a pretty different looking one.

Btw if you're curious about TBCs, there's a list of chips used in the AVT 8710/CTB 100 TBCs, there's a list here, and some more info buried in the threads. These TBCs seem to have a separate ROM chip and a microcontroller.

The TVOne 1-TBC (newer with ghosting issues) we got here is even more fancy with an Altera Cyclone FPGA and a lot of memory.

I've been meaning to see if I can probe a bit at JTAG and/or I2C lines at some point in them, but haven't gotten around to it yet.

Thanks for correcting my caption. I wasn't 100% sure but wanted to make sure to be as specific as possible. I'm still learning. Thanks for the feedback and for the images. Those tbc's use very similar socket type chip. Is there anything in those images that shows why the units are bad? (Signs of a failed device)

Memory chips look like the OKI MSM518221 series. This is a 256K x 8 bit memory chip with independently-clocked input and output ports, intended for serial, first in first out access on its input and output ports. Per the datasheet, it's intended for use in TVs and other video devices and is conveniently sized to hold a single NTSC video field.

Those numbers check out. Assuming 720 pixels per scanline, at 262.5 scanlines per field, that's 189,000 pixels per field.


I've attached the datasheet for the memory, as well as the MCU from my previous post.

Given the above, I don't think the MCU is involved in the processing of the video; I don't think it has the power to keep up. I think the proc amp capability is done mostly in encoder or decoder chips, directed by the MCU.

From what I've seen, I think the general architecture of these devices goes as follows:

Analog Video (unstable vsync/hsync) in --> NTSC decoder --> dual port memory --> NTSC encoder --> Analog video out (stable vsync/hsync)

ITSM that the time stabilization comes from the fact that the memory A) has independent input and output ports and, B) those ports can be independently clocked. So the input NTSC encoder can feed pixels to the memory as it gets them from the VCR, and the NTSC encoder can drain the memory at a steady, stable rate with consistent hsync and vsync, making dropped frames on the input card much less likely. So long as the timing jitter of the input signal doesn't get too bad, buffer over/under-runs in the TBCs memory shouldn't be an issue.

TBC-3000 Main Chip - Sticker Removed
 

I got the heat sink in the mail today for the main chip on my TBC-3000 so as mentioned above, I am attaching some pictures of it. It is a Winbond chip as well but has some differences in the part numbers. This one is W78E52BP-40 (345GC22513570-812RB) where my TBC-4000 board had a W78E52P-24 (907GC184875602UU). I'm not sure of the differences but figured I'd share.

Did you find if the main chip on yours got warm?

Here's what the main chip on my TBC-3000 (bought from LS) looks like (I could take some better images with a proper camera if there's any interest):


Attachment 10683
Attachment 10684

The PBC is marked 1997 so it's a slightly older model. Seems they changed chips in some revision. I'm guessing the extra connectors on your TBC-4000 is the stuff for linking them up?

That's very interesting. A number of differences between the units. (Main chip set, old style jumper for pal/ntsc selection, ect...) I haven't personally confirmed the main chip heats up a bit but that seemed like the consensus. I haven't done any temp readings as I've got a bit sidetracked. I'm working on a diy VHS cleaner/polisher. I've got a few days left of work on that and then I'll be back to capturing.

-- merged --

Got around to putting the heatsinks on the bottom board of one of my TBC-4000's. I need to order more to finish the top board but this illustrates the clearance with heatsinks installed.

Hodgey,
I was able to do some temperature readings today to give us a general idea on how hot the chips get. Temps were taken with a cheap infared non contact thermometer so it's not 100% accurate but is interesting nonetheless.

TBC-3000 (This Unit has heat sinks installed on all chips where temp was measured)- After about 2 hours of running on a vhs capture. I ran the TBC for at least an hour with the top on the unit before removing it to take the temps.
Main Chip: 91.9 F
Medium Sized Chip:101.6 F
Small Chips:100.9 F
Memory:98.3 F

TBC-4000 - (This unit has no heat sinks installed)(I ran the vcr through an input on the top TBC-3000 board and took readings from that side of the board.) - I took base line, 26 minutes in, and at 60 minutes in. I'm currently still capturing this vhs and I'll check the temp readings again at the end and will post if the temps continue to rise.
Baseline Temps:
Main Chip:80.7 F
Medium Sized Chip:84.2 F
Small Chips:84.3 F
Memory:83.2 F

26 Minutes into Capture: (Removed top of unit to take temps and then replaced after temp readings.)
Main Chip:97.5 F
Medium Sized Chip:103.9 F
Small Chips:105.1 F
Memory:102.9 F

60 Minutes into Capture:
Main Chip:103.7 F
Medium Sized Chip:107.5 F
Small Chips:111.0 F
Memory:106.5 F

-- merged --

TBC-4000 - Top Board

Total Capture Time - 2:36
2:36 into Capture:

Main Chip:109.2 F
Medium Sized Chip:111.4 F
Small Chips:117.1 F
Memory:110.9 F