#149

Рет қаралды 9,836

Күн бұрын

Пікірлер: 87

@radiofhi 3 жыл бұрын

Thanks for sharing a great instructional video. Referencing the schematic and additional information on the circuit operation was really helpful. Replacing the electrolytic caps with higher voltage caps is a nice touch and good idea too. Fine Biz!

@TheRadioShop 3 жыл бұрын

You are welcome!

@dwlawson78 7 жыл бұрын

Thanks Buddy. Great work trying to quite this old gem alive and well. Looking forward to your next set of experiments for this rig.

@TheRadioShop 7 жыл бұрын

Thanks, more to come.

@mikesradiorepair 7 жыл бұрын

Old school is cool. :-) When you told me about the recommendation of pulling the working board and putting in the one that had already lost its memory to reprogram it I was sceptical. This proved that scepticism was correct.

@TheRadioShop 7 жыл бұрын

I have the feeling myself. But did not hurt to try. Took one for he team I guess. Actually two.

@wes11bravo 3 жыл бұрын

I did the PIEXX upgrade years ago. Now I just need to fix all the other problems and do the AM mod!

@n8nkqrp595 7 жыл бұрын

Great series. Thanks! If those people stop selling those boards, and you have one, you could always pop the EEPROM out and clone it. Then clone the PCB. Or build a poor man's version on perf board. It would be ugly but would work. Thanks again for the fun and interesting videos!

@M0UAW_IO83 7 жыл бұрын

The boards I've seen have another programmed chip on them, that chip can be protected against copying by 'blowing' a security fuse on the silicon so it's a good idea but likely to not work.

@TheRadioShop 7 жыл бұрын

Yep, Clint may be correct. I know if I was selling a board that had software on it that is how I would design it. If I was a designer / seller for profit.

@timbacchus 4 жыл бұрын

I've had an Icom 751 bought the year they first came out and still have the same battery. I did buy a new board many years ago with the permanent memory. I have never had to use it. I am lucky.

@rlgrlg-oh6cc 7 жыл бұрын

Probably a small adapter board could be designed which would permit reading and writing the RAM chips using a normal EPROM programmer. Lots of USB EPROM programmers can be used with modern PCs.

@TheRadioShop 7 жыл бұрын

That is correct, many possibilities at the moment. I am thinking Arduino.

@jaybats7865 5 жыл бұрын

Great video Buddy. You explain everything so well. Thanks for bringing us along

@randelstuckey5494 7 жыл бұрын

I really enjoyed this episode very much. I agree with you that there has to be a way to get the information off the old board. Paul on Mr. Carlson's Lab used the two AA battery trick but only just long enough to replace the lithium battery. I hope you find the solution for this issue.

@PapasDino 7 жыл бұрын

Look forward to see what you come up with via the logic analyzer...thanks for sharing Buddy! 73 - Dino KL0S

@TheRadioShop 7 жыл бұрын

Will be interesting. We have to map out this ram board. Thanks Dino.

@phildavies5833 7 жыл бұрын

I have just been through this myself on my IC-751, I built both types of programmer but the only one that did anything was the N2CBU version, i used an old Dell machine, booted to DOS via a USB stick and read the garbled contents ok, however i found an issue when writing back the "good" BIN files that you can download. Eventually i discovered that removing the first DATA byte from the file put the rest of it in the correct order for programming. The BIN files, once saved, are padded with an extra "00" byte between each byte of real data so in fact i removed the first 2 bytes from the file and this restored my 751 back to working order, however not being happy with that i decoded the information moved things about and added the 60M band too. If you look through the data as shown on screen you can see this data pattern - 81000002000543000014000596000057000599000050100593100054100597100058100590200051200544200015200597200000300 This breaks down to the following ranges with the LSB first so the first part is the 160m band starting at 1.800 and ending at 2.000Mhz 081000002000 - 160m band 543000014000 - 80m 596000057000 - 40m 599000050100 - 30m 593100054100 - 20m 597100058100 - 17m 590200051200 - 15m 544200015200 - 12m 597200000300 - 10m 73 de G0SXY

@TheRadioShop 7 жыл бұрын

Great information! Thanks for sharing.

@ne2i 7 жыл бұрын

Even Better, How bout giving it RS232 out to hook up to a computer to command the radio and frequency information. You need some sort of bootloader to load the program onto the chips.

@TheRadioShop 7 жыл бұрын

Interesting idea

@KellyMurphy 6 жыл бұрын

Looking at the schematic, you could do a 11 bit binary counter, increment it on the address lines, and read the 4 data lines. That will get you what's in the ram of the good board. (This could probably be done fairly easily) Once that's done you could do the same binary counter and "Playback" the memory contents to D0-D3. and write the data to it. This should be fairly easy using an Arduino Mega.

@TheRadioShop 6 жыл бұрын

Hi Kelly. Yes that is another platform I need to learn. I picked up an Auduino a few months back but have not had the time to get into it. I did have a guy start on it on the EEVBlog forum but never had the time to finish. One day I plan to try and figure it out.

@johninjersey 5 жыл бұрын

I just bought an R71A on eBay and am considering buying this ram board but I also just bought 4 pack of lithium batteries which is a lot cheaper and I may just replace the existing battery. I realize I must not let the board lose voltage so I will rig an extra battery connection and then remove the old one and replace it. And if I screw up I can buy this board so...

@tlrptg 7 жыл бұрын

it was worth trying. looks like the CPU uses this module as a RAM too, not just as backup, and the module has some protected areas where the CPU can read data but cannot write data. Try to get a cheap computer or laptop which has a hardware LPT port (USB emulated parallel ports are not recognized by DOS), and boot a Windows 98 CD in DOS mode. That's the closest thing to pure old style DOS. Also make sure that the first partition on that hard drive is formatted in FAT16 system, and the partition is not bigger than 500Mb. Copy the program and the HEX there, and run it. (this is valid for older computer BIOS upgrades too). Again, sorry that it did not work as i hoped it would.

@TheRadioShop 7 жыл бұрын

Hey, it is all in the name of science. Plus it was fun to experiment with. I have not ditched it also. Could be as simple as adding a few jumpers and a signal to make it work. As soon as I saw the display go "0" I knew we had an issue. Going to get an auduino and do some playing around next. Thanks, this was fun.

@dennisqwertyuiop 7 жыл бұрын

looking forward to programming,,nice work

@TheRadioShop 7 жыл бұрын

Thanks Dennis.

@loughkb 7 жыл бұрын

Have you tried working with DOSbox? It runs on all modern machines and all platforms and is basically a virtual DOS computer. It supports Serial and parallel interfaces, so there's a chance it might work with your programming software.

@TheRadioShop 7 жыл бұрын

Hi Kevin, Until recently I did not know that was an option. Several folks have mentioned this since the video. I am going to pick up a parallel card and give this a try. Thanks my friend.

@shoppersplace 2 жыл бұрын

Replaced board, on this hamfest find, and display came back to life. A bit of hissing from speaker, but not picking up anything. All antenna connections good, and jumper on rear good. Any clues? Thanks

@alpcns 5 жыл бұрын

How about running DosBox on a modern computer, emulating a old IBM PC? That way you can run the old DOS software. Serial communication etc. might be supported.

@scottlee1211 7 жыл бұрын

Great video Buddy! Damn, ham rigs sure are complicated!

@TheRadioShop 7 жыл бұрын

Thanks Scott, and yes they are lol.

@rong3194 7 жыл бұрын

That's why I like building QRP kits myself. I can build them and understand them. Simple kits are fun. The high end Elecrafts, however are not really kits, and are every bit as complicated as these Icoms.

@johninjersey 3 жыл бұрын

I got my 745 a few days ago and I'm noticing a problem and I hope you know what it is Buddy. When I first turn it on after being off overnight the VFO knob doesnt work. I turn it but the freq doesnt change. The freq display is slightly off from when I turned it off and the last digit is flickering a bit. Then I go back and forth Memory/VFO and it starts working. I'm hoping its this RAM battery? Any ideas?

@worldradio456uk5 7 жыл бұрын

Hi there buddy. Excellent video as usual. I know this is an old rig but Jesus what was icom thinking! Could only be done like that on purpose to make tons of money a few years later when the batteries die. Iam sure the other brands didn't have as much trouble as this . Happy Christmas and New year. 73s rich.

@ethicalfarmer7424 7 жыл бұрын

It was great for Icom at the time you would have to mail to Icom service dept, they would re-programme replace battery & ship back to you all at your cost, 73 Vk2 tgr

@worldradio456uk5 7 жыл бұрын

Hi there. I think what is needed is for buddy and the other programming/code experts on KZbin to all get together and make a complete redesign of the icom board. Iam sure they would sell by the truck load. 73s. Happy Xmas.

@stevejones8665 7 жыл бұрын

Hi Bud It Seems a bit odd to me that Icom would fit a board that would brick the rig just because the battery went flat...I have replaced volatile ram batteries in the past and on power up the default settings get rewritten to the prom, are you sure the ram board doesn't have faulty default settings chip on there so when a new back up battery is fitted it cannot rewrite the defaults.....this would also explain how someone else could swap boards whilst powered up and there's would then write the info back to the good working board from the default ram settings which are then used by the Microprocessor....just a thought I may be totally wrong but believe discussion helps.....All the very best wishes to you and your family for a Great Christmas and New Year..

@TheRadioShop 7 жыл бұрын

Hi Steve, Great comment and thoughts on this. First of all it was way cheaper than an eprom solution at the time. Eproms were slowly making it into the seen then. This board I tested with was pulled from a working radio. When the battery was removed it last it's memory and died. N2CBU verified this information back in the early 90's. The first problem with the board swap software upload is when you remove the ram the radio's cpu goes into a no memory state. hence the display goes all zeros. I even tried a know working board off came with the battery removed, same problem. Now I have 2 dead boards.

@stevejones8665 7 жыл бұрын

The Radio Shop Thanks for the reply...That is Crazy of Icom to design it like that lol..same old story I guess too many pen pushers in design department instead of Asking the good guys like yourself who go to component level to fix things with more brains in your little toe than the Designers have put together lol....Good on yer Bud and good luck fixing all the 745s...it seems to be the silly season with everyone needing things fixed ☺ I have a heap of stuff to look at from Washing machines to Xmas decorations to fix lol all good fun and keeps are grey matter working...take care Bud....Steve Liverpool UK M0BFM 03:12 am and watching your Videos ☺

@texasvarmint9542 7 жыл бұрын

Good video, Buddy. I was wondering about that comment and how that could work.

@TheRadioShop 7 жыл бұрын

Thanks James, and now we know..

@rodrigogomes7378 6 жыл бұрын

Hello, I have a radio of this and I need help to program this memory again, I could not in Brazil, I need the diagram to connect to the recording interface, if you can help me, I'm very grateful ...

@evandroesm2009 6 жыл бұрын

Hello, good morning my friend! I have a radio identical to Mr., but in USB it has a fine noise as if it had a cricket in the sound. could or would you have any tips on this defect? Thank you for your help, good morning!

@TheRadioShop 6 жыл бұрын

Hi, I would start with the filter.

@vetterfellow 7 жыл бұрын

Buddy; This reminded me of the old Mr. Wizard's world. Kind of a scientific results of a problem. I like your comparison of a radio that doesn't work, " A Brick " That's Hilarious :-D Thanks for another one.... Angelo.

@TheRadioShop 7 жыл бұрын

Thanks Angelo. Yes this dead battery makes for a good brick of a radio. Really makes me wonder how many are sitting in folks closets and basements. Guess we can say just another brick in the wall.

@billrenfro9798 7 жыл бұрын

Just thinking outside the box here, but would it be possible to piggyback the non working board onto a working board so that it could read the data from the radio?

@TheRadioShop 7 жыл бұрын

The way it is designed nope. It simply cannot write the bytes to the chip. Would be nice yes.

@rong3194 7 жыл бұрын

Thanks for another relaxing video, Buddy. Nice to see you post one on a Thursday. Also, thanks for the link to EEV. (However, I like your accent better than Dave's)

@TheRadioShop 7 жыл бұрын

Thanks Ron. Yes this was eating at me and had to do it early in the week. Love the comment on the accent!

@dusseli81 Жыл бұрын

Hello, I am an icom 745 user. Running out of RAM battery worries me a lot. How do we know when the battery is low? What should I do if the memory is erased? How do I get hex files? thanks. TA2IV 73

@WaterFaucet24 6 ай бұрын

I have a 745 and had the same worry as you. I just bought and replaced the board with a PIEXX version. It worked fine and my frequencies/VFO work fine after the replacement.

@1112223333111 7 жыл бұрын

I think if you piggy-back the dead board with a new battery onto the good one, power up the radio, wait a second then power it off, the piggy-backed one should be cloned

@TheRadioShop 7 жыл бұрын

This thought did cross my mind. really need to know more about what is going on in that circuit. Icom failed to tell us this in the SM.

@phildavies5833 7 жыл бұрын

Have emailed you the ram board circuit.

@TheRadioShop 7 жыл бұрын

Very nice of you Phil. Thank you very much

@mhowlett62 7 жыл бұрын

ICOM Canada has a service procedure on its web site covering this... www.icomcanada.com/techbulletin/tb1/ram_card.htm

@TheRadioShop 7 жыл бұрын

Yes seen that one. Shows the correct way to replace that battery before it goes dead.

@Radionut 6 жыл бұрын

You talk about putting two AA batteries inside the case. Where do those two AA batteries to hook up

@TheRadioShop 6 жыл бұрын

Just mount a battery holder that holds two AA batteries in series. This connects to the battery that is mounted on the ram unit. It is a backup in case the soldered in battery goes dead.

@vhfgamer 7 жыл бұрын

I wonder if your ms DOS programmer would run in DOSbox. Google DOSbox if you are not familiar with it but basically its a DOS emulator terminal you can run in a modern computer. It is typically used for video games but I do not see any reason why it wouldn't work for this. You can even configure it to emulate specific hardware from the DOS era such as everything from the original IBM pc (which I happen to own a real one YAY) all the way up to a pentium based dos rig and everything in between.

@TheRadioShop 7 жыл бұрын

Very interesting yes, But to answer the question? Nope. The old DOS programmer I have has a special interface PCI buss card. Modern computers do not have the slot,, Well most of them do not.

@fenderblues1744 7 жыл бұрын

Buddy have seen this, if not here is the link. [PDF]Procedure to re-program the IC-751 or IC-745 RAM board (in ...

@TheRadioShop 7 жыл бұрын

Link did not show, try posting it with no other comment

@fenderblues1744 7 жыл бұрын

The Radio Shop Hi Buddy. I'll have to do it tomorrow now. We're in bed over here. I'll make sure you get it.

@1112223333111 7 жыл бұрын

I think you said dont touch the vfo and power cycle the radio first. you did the opposite.

@TheRadioShop 7 жыл бұрын

That was due to already knowing this was a fail. As soon as I lifted the good board out and the radio went to all "0" I knew it was a lost game. I tried this several times doing it different ways before and after the video.

@fenderblues1744 7 жыл бұрын

Buddy. I think these are the programing files I found

@TheRadioShop 7 жыл бұрын

Yes they are the hex and bin files. Turns out I already had these from a few years back. Thanks