EEVBlog

What was technology like inside a 1994 Motorola MicroTAC 7200 International GSM mobile phone?
The original sales brochure! www.eevblog.org/files/Brochure...
Brick Mobile: • EEVblog #243 - Vintage...
68300: docs-asia.electrocomponents.co...
MC14447: www.dzjsw.com/jcdl/m/MC14443.pdf
PIC16C57: ww1.microchip.com/downloads/en...
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[@vincifrisco]

I had one in circa 1994-1995, and actually, I triple assure you in remote locations the reception was better than my actual 3G/4G phone. By the way, these chips are huge!

[@douro20]

The AT&T 1616S30 is a DSP used for GSM speech coding. It has a 12Kx16 PROM and 2Kx16 DRAM built-in. It was most likely made at AT&T Technologies' Reading Works. I wouldn't be surprised if a similar chip is still available.

[@Mobin92]

At first I was like "Wow how technology has advanced in a few years..." But then I realised, that phone is nearly 20 years old! 0o

[@PremiumFuelOnly]

My truck is that old, still works. Cant be that old.

[@SuperMarioLecter]

Another vintage teardown? Hooray! Keep 'em coming!

[@SuperJourneyer]

Thanks Dave! I enjoyed that blog.

[@GaRbAllZ]

Thanks for taking the time to do the video Dave!

[@PremiumFuelOnly]

wow, what have i been missing by not watching this channel? Subscribed...

[@josephbeasley5210]

The AT&T chip is either the baseband processor or the DSP. in order to be a DIGITAL phone it has to have a DSP for processing telephony signals.The Motorola 68000 chip would be your applications processor; or in this case the processor controlling the display, keypad and speaker. Like modern mobile phones, this device would be running a dual operating system.The main OS would be some form of Motorola DOS or something like that, while you would have a protected real time OS specifically for the radio.

[@anttipeltola8578]

My first mobile phone was a MicroTAC 5200 I got as gift from my sister once she got a new Nokia around 1997. Eventually swapped it in the late 1990s because it couldn't send texts and they were in vogue back then.

[@jckrarup]

The 43E04 is the Bus Interface Controller (BIC) that does the coding for the service bus in the acessory connector - I think it was manchester coded. The Carkit would use the BIC bus and also have the BIC chip in it. More important, the EMMI box used to service and firmware update these used that BIC. People built their own EMMIboxes with chips scavenged from older phones.

[@SeanBZA]

Hey, I had 2 of those bricks. Still have the charger in parts, reused the wall wart. 8 hour battery life.............. They did do calls though, even if you were chained to a car charger on the way to work and home and needed the desk unit during the day. Extended battery was double the size and gave 24 hours of standby, what a luxury.

[@georgebelev1900]

Motorola was simply QUALITY back in the day ! I have the same motorola and it WORKS! Imagine that

[@vladimirtodoroski]

Same thing. My Motorola still works today, 26 years after it left the factory. The only problem is the battery doesn't hold charge.

[@dBm_drillingbits]

The big block made out out dielectric material is not a SAW filter is in fact a duplex filter used even now on one freq you receive and on one you transmit, and the block which you named RF voodoo I bet my money is the RF amplifier. Nice tear down more RF stuff. Keep up the good work! :)

[@chrispychickin]

I love the video Dave, it was really interesting to hear some of your knowledge about the hybrid modules. they've always fascinated me, but I don't know jack about them! peace chris

[@javipall]

video processing, I can not wait!

[@turboslag]

Ah, memories! I had one of these, in fact, I had the 'rola brick phone as soon as it was available in the UK! £2500 and £0.50/min or part min! My Father had an even bigger brick phone though, the Mitsubishi Roamer, that was actually difficult to hold it was so wide, with the battery on the side. And it weighed almost 1KG!! Battery life on either was appalling, down in the 2-3 hours area if you used it frequently during the day, hence the need for a second battery. Even that level of usability was transformational in business though.

[@SeanBZA]

3 settings on the ringer, off, very soft and just a little bit louder. The ATT chip is the GSM encoder, I remember on the ones I took apart it was not ATT branded but was a regular Motorola part. Probably proprietary settings in the chip for working on the ATT system, other markets were actually standardised. Power it on and it will probably still work.

[@jckrarup]

The AT&T chip is the DSP, since a lot of the stuff couldnt run on the 68k - They also used a 56156 from TI or Lucent in other designs.

[@ivantovu-kalott8460]

damn good and bad memories , have reflowed about 1000 of those in the day...

[@matooo95]

I still have my first cell phone. Nokia from 1997. I disassembled it 1 year ago and I was fascinated by the chips. They were marked as LISA, BART and so on from The Simpsons. I love how the designers made their job back in those days.

[@TheBadFred]

I had one one of those in 1995, it was the only way to get a telephone line at that time in Dresden.

[@WooShell]

That beast was my second mobile phone back in the 90s.. it followed a Motorola Tac3000 (the classic bone/handlebar phone). I wondered about a lot of the stuff inside when I finally tore it down - now I'm getting it explained 20 years later ;)

[@berni8k]

That module is most likely a TX power amplifier as these phones have many watts of TX power and the goldbond jumpers over the PCB inductor might be to configure it for different working frequency for certain parts of the world.

[@larryrussell5440]

Agreed. This would have been AT&T Microelectronics in Allentown, PA. They did primarily specialty chips like DSPs once they figured out there was too much price competition in memory and microprocessor chips. This would have been before Lucent spun off from AT&T in 1997.

[@djneon12]

we still use the 16f54 at school. and we learn to program it in assembler :)

[@dBm_drillingbits]

That is the best guess and keeping in mind PLL's back then were still a big deal made with serious HW not junk PLL embedded nowadays.

[@Hybrid330i]

ahhh I remember the analogue versions of these. Use to ground the center pin and put the thing into 'test' mode .. and scan all channels up and down the range on the local cell towers. very interesting results haha

[@show1111yes2]

Are you very knowledgable about this phone and how it works?

[@Hybrid330i]

***** I haven't mucked around with it for 20 years so cant remember the exact commands, no doubt you can trawl google if you're interested. But once your in the test menu there are command to scan channels. This is all obsolete these days with digital cell networks.

[@show1111yes2]

Interesting, i've been researching this phone and how it works for a year now and are looking for the most probable way to change the frequency channel to 1900 or 850 mhz. Most say this isn't possible, however many others say it is. So I am planning to either work on the hardware or try two other reverse engineering techniques. Thanks anyway, I am just looking for someone who can help me understand what I need to do and how to do it.

[@XrudzX]

Got one handed down, i did not have any problems with it at all, really a nice phone back in the day.

[@petersage5157]

6:28 Dave, please; that's a coupling capacitor. I'm mostly an AF guy, but I remember building a few AM radio kits, and the antennas were typically coupled to the tuning coil through a few dozen pF. I couldn't be bothered to do the math, but I'd wager that if there's even a few pF capacitance between the coil and the antenna it's gonna look like a dead short at 900MHz while blocking lower frequency energy that could bugger the receiver.

[@EEVblog]

Then why don't you contribute your vast knowledge of what those custom chips are and other stuff?

[@ianc4901]

You bent the tip of your pointer ! Bagga !!

[@202Electrics]

You should get a hand on an old NMT car-phone (also motorola) .... those huge devices have a lot of interesting stuff inside. even the RF amplifier module is re-usable !

[@Arabhacks]

The can is the duplexer, this handset can operate both analog and GSM. The AT&T chip is under license, they held the patents but the chip was produced by Motorola, it is the codec chip. The 2 PROM chips held the ESN, one for the Analog side of things and other the IMEI for the Digital realm. This was produced when cloning a handset or SIM card was super easy. Not that it is hard now. The GSM SIM cards are a bit harder now but it can be done, the Ki is the answer.

[@josephbeasley5210]

So in other words it's the baseband processor??

[@gollumondrugs]

If that CPU is a 68000 variant it is HUGE! There were chips at the time such as the 68EC020 (68020) that were tiny in comparison with this.

[@spodula]

the 28C64 is a EEprom, not an OTP. Its probably where it stores its configuration. Acts like a RAM chip, but survives power downs.

[@donpalmera]

The 68332 is a 68000 + a ton of peripherals hence the bigger package to break out the pins.

[@Sevalecan]

I suspect the date code on the back of the device was not "26th week", but 260th day. Would seem to fit with the 38th week you found on that other device inside of it, since 260/7 is 37.14 . Looks very similar to the Julian dates we use where I work to identify parts.

[@HambertHM]

"On all models, and unlike the Motorola DynaTAC, the plastic antenna served no functional purpose, and was strictly for aesthetics." (Wikipedia)

[@Renatodonadio]

1) The AT&T chip probably was used to support a communication standard different from GSM at the time supported by AT&T (maybe ETACS) sort of like today happens with Verizon in the US, that still has a SIM-less standard that forced Apple to do a special version of the iPhone 4 for Verizon customers with only the chip (with no SIM card) then included both the SIM and the chip on later models 2) The ringtone was a two tone high-low bleep repeated something like 20-30 times in two "bursts" sounding like "breep-breep"

[@josephbeasley5210]

The AT&T chip is the telephony DSP.

[@TheOriginalEviltech]

Those are custom transistors and diodes. Those phones had about 5-10W transmitters on them... Powerful RF transistors are expencive and add induction to the circuits so it makes alot of sense to make them built in to the transmitter/ transiver module. Stop doing those scope review's! We want videos like this one!!!

[@Tutoelectro1]

How long did usually the battery of those lasted?

[@billa8671]

the ringtone would've been a simple chirp or ring. Nokia wrote the software for piezoelectric ringers to use MIDI music some time in the late 90's

[@madjimms]

Lots of gold on that phone...

[@MisterMosfet]

I thought they put those antenna on there because the phone companies believed that customers wouldn't want to buy phones with no external antenna because of how every good radio product had a huge antenna on it..

[@Polished_Perspective]

Whoever thought of putting fractal antennas in cell phones was a genius.

[@twocvbloke]

I have the slightly higher model of this phone myself, the 7300, worked fine the last time I used it, had better signal than my more modern phone I had at the time too on the same network... :)

[@vladimirtodoroski]

You meant the 7500. There was no 7300 model. Motorola went from 7200 directly to 7500.

[@Niever]

If it's what I am seeing, that's not a sim card slot dude, it's the wall charger slot.

[@chimetrooper]

Yeah, mine still works but batteries seem to be getting harder to get. Any suggestions anyone?

[@prankmypants]

that antenna looks like the primary and secondary of a tesla coil. i wonder if it functions much the same but with reverse flow.

[@TheBadFred]

Lot's of gold inside. I would guess more than in a current smartphone.

[@MrJohnboyofsj]

It really really sucks sooo bad that my high school cancelled the micro electronics class. I would like to understand them. Lol

[@davidkierzkowski]

lots of gold!

[@sparticus214]

The antenna design is supposed to tune different frequency.

[@TofuInc]

Well I guess they can make a phone just for you that has 12 pullout antennas because the rest of us are fine with a couple of embedded fractal antennas.

[@IliyanTrayanov]

I think hes doing it, I favour with his video ;) LIKE!

[@NothingAnon]

Three-Five went out of business back in 2005.

[@TheOriginalEviltech]

Finaly!!!

[@douro20]

I'd imagine that the firmware barely taxes that 32-bit 68000-based microcontroller.

[@FrumpyFriend39]

But, isn't Motorola still dominating with the Droid? :P

[@TheJMan11000111]

Awesome

[@opelize]

Only 480P so far??? Dammit youtube!

[@2nd_Channel]

My first company phone, imposible to kill, even after we throw it off a 4 story building all it needed was to reconnect the battery and it was fine. Also dropped it in a bathtub, 1 day oon the radiator and it was fine again...

[@opelize]

Yes I edited my reply to you to point out my 'so far' comment

[@dumass00072]

I knew it. I was saying to myself "Look under the stickers!"lol

[@mktward]

Cool!

[@Landrew0]

I remember the 3 loud beeps in your ear when phone lost the signal.

[@DAVIDGREGORYKERR]

I had a Motorola phone which is not Y2K complient.

[@ceriand]

The AT&T chip was probably made by the modern day Lucent.

[@chippy273]

19:40 Look it has a Diode in there (second from left), I assume by the marking. So Could that be a varicap and the whole thing the VCO ? No DDS in there, it's an oldschool VCO with a varicap, maybe the chip below is a PLL controller ?

[@dumbo800]

1994 I was 5 years old.

[@show1111yes2]

I'm trying to change the bandwidth of my 5200 which part on that circuit board controls that? Is it the silver box directly behind the antenna? the one with the serial tag? Trying to convert mine to gsm 1900

[@tonytoy7673]

how did you remove the the back without breaking the 6 locks? you skipped that part

[@rexuzelac5493]

C24 (near the baby-blue colored rectangular part) is installed in the wrong set of holes, no?

[@pastedtomato]

My dad used to own one of these, my big sister throwed it to a fishbowl, my dad only taked it out of the fishbowl, put it in rice, and whoala, it was working (sorry for my bad english)

[@mpex2006km]

RF VOODOO STAF.... Great

[@ryansoh333]

Ah, gotcha. Thanks.

[@g6qwerty]

Hey i Just saw this in a Korean movie, Run away from home. or similar.

[@alexandrossotiropoulos5621]

Ooooo! this charger has quality in it! The new chargers for smartphones are not on a par with it.

[@rubusroo68]

size of the device must've been dictated by battery size back then

[@joblessalex]

Testing to see if it worked. Phones back then were really loud and annoying.

[@Debraj1978]

1994 -- I did not even had a phone, leave mobile phone.

[@alexandrossotiropoulos5621]

I think when the phone has not signal. iIs it the curcuit in 28.11 responsible!

[@stonent]

Video unavailable?! Denied!

[@zadatakz]

Someone count how many times he says "you know"

[@Dibblah1900]

motpages.50webs.org layout 8200c.txt - spaces are slashes. The AT&T chip is " DSP incl. 12Kx16 bit ROM & 2Kx16 bit DPRAM (U801 Speech Coder)"

[@radikalq3]

And the Mail Bag? :(

[@WarthogRacer]

Vintage? Ha! My parents got a free bag phone for buying gas in 90/91 :)

[@rubusroo68]

it's still processing...

[@opelize]

I know - that's why I said 'so far'... just complaining :)

[@unolisto]

because of the microswitch/sim card fiasco

[@oddarnebeck]

How does the battery charger convert the mains to 5V? I couln't see a transformer in the charger circuit.

[@josephbeasley5210]

SMPS - switched mode power supply.

[@josephbeasley5210]

Essentially; the mains power is first converted to DC, then stepped down to an intermediate voltage using resistors. The intermediate voltage is fed into an oscillator converting back to AC at a higher frequency ( like 120Hz or so ) then down-stepped with a HF transformer to 5V, then rectified, filtered and regulated.

[@theCpuBuilder]

or co-processors :D

[@GeorgeGraves]

Repost! ;)

[@Modinthalis]

This is the phone that hacker Kevin Mitnick "stole" the source code for while on the run from the FBI :)

[@ryansoh333]

What was wrong with the first upload?

[@thekaiser4333]

Why is there this black rubber stuff on U2 at 21:02?

[@MartinKL]

+The Kaiser that's a chip on board - COB. They put a silicon die right on the PCB to save space. It's common in very high volume products.

[@thekaiser4333]

Martin K Thank you. And why the black rubber? Isn't solder not good enough anymore these days?

[@MartinKL]

+The Kaiser solder would short out the bond wires. That wouldn't be good.

[@thekaiser4333]

Martin K How are the bond wires soldered or contacted/attached?

[@alexandrossotiropoulos5621]

poor phone! It will never ring again!

[@Shroommduke]

NO KIDDING! people jibber jabber, cluck and cackle in public, it's like the worlds gone mad! It used to be that only crazy people walked down the street talking to themselves but now everyones doing it.

[@JeremyHongelectronics]

Nooooooooo denied

[@Jason-pn9to]

lol rf voodoo