MB 8719 chip in place of RCI 8719

[wyatt knight]

I picked up a new pll chip at the cb shop today. It is the MB 8719 chip instead of the RCI 8719. Is there anything I need to do special when I put this chip in or is it a direct replacement like I was told. I'm just double checking as the $5.00 I paid wasn't much but the cb shop is about a 100 mile round trip for me and it's not often that I'm close enough to detour to go by there and I don't want to blow this chip if I can help it.

[Polish Eagle]

Sorry I can't help you with your question but I have one for you. Which 959 runs
better. MOSFET or 1969?

[wyatt knight]

I've read that the mosfet one would tune better but my meter says there about even.

[Night Crawler]

I picked up a new pll chip at the cb shop today. It is the MB 8719 chip instead of the RCI 8719. Is there anything I need to do special when I put this chip in or is it a direct replacement like I was told.

There's nothing special you have to do to install it the MB-8719 can be used as a direct replacement for the RCI-8719.

The difference between the two chips is that the RCI-8719 uses a 6 bit BCD binary programmable divide-by-N counter and the MB-8719 use a 7 bit which means that the MB-8719 is capable of more frequency coverage if you decide to program it to do so.

[Polish Eagle]

The hype is how they get us to spend our money! Thanks for the response. I'll keep running my
35 year old Cobra. And the "new" radios as well.

[wyatt knight]

Thanks, that's what I needed to know. I've got my other 959 expanded succesfully but I guess the greater coverage would come with an expansion board instead of the switches. I also picked up a working Cobra 29 LTD Classic made in the Phillipines July 1989, no mic but I've got a mic, for $5.00. It's dirty as heck and needs the channel indicator replaced but I think I got a deal.

[TheCBDoctor]

Hi wyatt knight

I would not use the Toshiba MB-8719 in the DX-959. The MB-8719 is obsolete and can not be found readily. They go for $25 when you can find them. I would save that PLL for a radio that absolutely needs it. You stole that MB-8719 for $5. I would put it on eBay for $25; you will get it.

The RCI-8719 goes for $7. If you want to double your money I will give you $10 for the Toshiba MB-8719.

Respectfully,

[wyatt knight]

Thanks for the offer CB Doctor. Considering the scarecity of this chip, I believe I'll keep it. I might not put it in my 959 but I do have a Cobra 142 that does have that same chip. I saw what they were going for on E-Bay so I'm pleased with the deal I got. I had asked him for the RCI 8719 chip and he said no problem. He got up and started looking through his chips and it started to look like he didn't have one and then he came across this one and told me it would work fine and that it would work in several other radios as well, one of which is one of my base radios. My favorite one.

[genesbro]

I was gona say get some more of those plls and I would gladly pay you for them, WOW!!!!!! I buy radios that are being sold as is for as cheap as I can get them that have that pll in them myself so I have spares. Congrats on the great deal!

[wyatt knight]

It was apparently the only one he had for my radio. I don't get down there much due to how far it is but I've been pleased every time I've been there.

[hellblade]

I have 2 of those that came out of the older 148's pulled one out of a 148 that the whole board was cracked from being Droped
and other was one purchased off ebay listed for parts should i hang on 2 them or sell them i have a 1988 cobra 148gtl that works great only thing done to it was add chanels

[genesbro]

I would keep at least on for a spare for sure, you never know it may never be needed but if it is they are no longer made so better safe than sorry.

[hellblade]

ok will do thanks

[wyatt knight]

I went and got a chip socket from R.S. for 0.48 cents the other day and decided to put it in my goofed up 959. It went in with no trouble and the chip I removed is still useable. Since I had a chip socket in there I decided to try that MB 8719 chip to see if it would work in my radio until I get the replacement RCI 8719-99 to go back in it. Well it didn't work in my radio. The frequency counter was showing about 4 channels low, 23 was showing close to 27.185 MHZ, and it wouldn't settle and stay on that even. The counter kept goimg up and down. I pulled the chip out, after I disconnected it from power and cycled the on switch several times. I then put the chip I desoldered from this radio back in via the chip socket and it went back on frequency, except for it's original problem. The point is that the MB 8719 is not a direct replacement for this particular 959 that I own, a mosfet version. I do not know if the fact that this is a mosfet version or if there is some other reason it wouldn't work in my radio or not but I do have a radio that this chip will fit, a Cobra 142, and the RCI chip is available so there's no loss on my end. Just info if anybody else is thinking of changing their chip.

[Night Crawler]

Possibly the MB8719 might be defective or the pull down resistors on the channel selector in the 959 have to be removed those resistors aren't needed when using a MB8719 only the RCI8719.

[wyatt knight]

Well maybe it's those pulldown resistors. I found another post about them somewhere really late last night. I don't plan on removing them from my radio since I just don't see any benefit in doing so when the correct chip is readily available for this radio. The MB 8719 may give greater frequency coverage when installed correctly but I don't plan on expanding the channels to the point that I would benefit from that greater coverage anyways. The LessComm board provides pretty good coverage without having to change the pll from what I've read so if I go that far I may just do that instead. Also, around my area a 10K switch may be usefull.

[wyatt knight]

Just a thought, since the RCI 8719 is listed as being interchangable with the MB 8719, and it would not work due to pull down resistors (?) being in place in my radio that is not needed for that chip, what would the RCI 8719 chip do if installed in a radio that did not have the needed pull down resistors. What would have to be done to make that chip work in say a Cobra 142? I ask since I have one and the MB 8719 chip I have I believe is good, Its not been soldered in a board before, but there's no real way to test this chip other than installing it is there? So if I needed to install this chip and it didn't work, what could be done to get this radio back going with the more easily aquired and cheaper RCI 8719 chip. I really like this radio and have made several DX contacts with this radio and though I would like to have a new Galaxy 2547, I'd like to be able to keep this radio going.