Jornada 680 headphone mod

Hello everyone, this is my first post here but I have been lurking in the forum for a while, I have really enjoyed your posts.

I recently ordered a HP jornada 680e from tigerdirect and have learned that it has no headphone jack and has a terrible internal speaker. I imagine it would be a pretty simple task to wire in a headphone jack by myself, but there are a few questions I was wondering if you guys could help me with.

I have plenty of experiene with electronics (mostly with amplifier and speaker wiring) but no specific specialized knowledge, so I'm afraid of some theoretical limitations that may mess up my new HPC. Presumably if I just get a mono headphone jack and replace the current speaker with that, it should function properly. (I would of course loose the internal speaker, but I don't care about that)

The issues I'm worried about are the following:
-First of all, impedence. What kind of resistance is acceptable on that circut? Would it be safe just to switch from the tiny speaker to my much larger headphones? I don't want to overwork whatever tiny amplifier is in the unit. I'm usualy a trial and error type of guy, but I'm not willing to take a risk this time.
-Would the sound quality be any good anyhow? I doubt they designed the unit for great sound output or volume. I don't want to go through all the work of wiring the jack and modding the case just to find that my mp3s sound like a whisper.
-It's mono-only, right?

I was planning on just simply testing it out quickly when I get the unit, does this pose any risk?

Thanks for the comments!

I dont think Ohms would be a problem. Your headphones are what? 16 Ohm? Then wire in a Headphone jack and mount on the side. Question is this. Is there enough room to mount the jack?
Stereo or Mono? The onboard speaker is Mono. If you can get the right jack, Then you would get Mono out of both ear pieces.
Sound Quality? You would be limited to what the sound chip is capable of.
MP3's? Wouldnt you need software to decode them?
Oh yeah before I forget.
WELCOME to the CLUB!!
Chris

Here is the low doen on adding a Phones socket to the 680:
http://www.geocities.co.jp/HeartLand-Suzuran/1004/jor680.html

I have raised the question myself and so far got no answer. I am sure you could successfully install a jack in place of the 20- cent speaker. If key click is important to you, you must be willing to type with ear buds or phones. Don't expect much volume. Although there is plenty enough amplification to stress that speaker at half volume.

You may be able to get more technical info by firing an email at HP tech. I'd ask for the technical schematic. Some PDA makers have turned over a copy for a device that is abandoned by the firm. HP has already abandoned handhelds. I hear NEC, the other maker of practical handheld mobile devices, recently decided to abandon clam shell style handhelds. The NEC 900 is a powerful beauty. I suspect Microsoft had something to do with it. Gates is hostile to PDAs becoming very practical, which is why HP makes very high quality Thin Clients (full sized smart dumb terminals but not an independent "Thin" PC, which would save people considerable money and save a lot of people big headaches caused by Microsoft software bloat and plain sloppy code.

Keep in mind that PDAs and especially handhelds are very power efficient. Most run on 3.7 volt 750 Ahm lithium ions. The 680e is designed and made for hardware adaptivity. There used to be a small daughter board for upgrading RAM memory and the ROM chip. I believe the ROM chip is removeable, a rare thing in mobile PCs.

One advantage Jornadas give you is their Hitachi processor, which plays a large part in why Jornadas provide 7 plus hours active use on a single charge. No Intel driven PDA can come close to that ! The explanation isn't size, since Tablet PCs are larger than Handhelds but do not provide 7 plus hour active use.

I just successfully adapted the 680e serial cable to USB 1.1 .... Have you considered doing something about sound by way of the serial cable converted to USB 1.1?
Also, you are aware of artificial stereo sound by way of external electronic means?
Get some Torx screwdrivers (T4 -T9 Husky brand at Home Depot or Home Depot online for $5.97), remove the custom base plate and you will find the CF Card Slot. It works. I believe there is a mobile device sound solution that rides on a CF card.



For MP3, you have the wrong Jornada. The 700 series, particularly the 728 would have made you happier. Personally, I see Handhelds as a MP3 big player, when you can get a tiny Casio BE-300 that has excellent stereo sound. You can one used on eBay for about $50

Thanks for the info guys! From what I can read on that japanese site, the sound quality will be AM at best, and it also says that there isn't room in the case to fit the jack. So I guess I'm gonna shelve this project.

I'm still really excited about getting my Jornada though. I got it mainly for taking notes and doing homework on the go but it really seems to have a lot more potential than that hidden beneath the surface. I'm sure that it will rarely leave my side once the UPS guy shows up and I get to play with my new toy.

I'm pretty interested in the serial-USB mod that you mentioned. I think I saw you discussing it in another thread, I'll go there to learn about it.

I like this guy.

I am going to attempt this mod. But I cant read the article.
Looking at the pics, I see he is using a Capacitor next to the jack. Wonder why?
Chris

i again tell you: jornada 720/728 has *intel* strongarm and does not have less battery life. i get around 9 hours out of my battery with normal use (more than that if only reading mode), 7-8 with wifi.

You are from Budapest...cool! I'm Hungarian but live in Alberta and speak almost none :-(. I should learn...anyways, you are getting that much battery life? It's normal for that to wear over time though, right? My 690 is giving me 3-5 hours now depending on brightness and wifi usage...I wish it was 8-9.

Steve
Istvan

The batteries are consumable parts, and most of them will hold only a few hundred charges before getting severely handicapped or dying, so if it's been used it a lot, it's normal that it's capacity has diminished.

In other subject, on SH3 Jornada devices (6xx series) the maximum battery life HP claims is about 8 hours for the default 1500 mAh. but of course you can buy a J728 battery (i believe it's 1950 mAh) or an extended battery (4500 mAh), but that one makes the devices bulky IMO.

If you want extra batteries another forum user is selling second hand ones, and they have still good life on them (words from a satisfied buyer).

It looks like he wired a switch so that he can use the built in speaker and the headphones, at least thats what I can tell from the site. I will be going off to Addison's to see if I can find a headphone jack to fit in my Dutch Railway 680e. From removing the fake bottom i am pretty confident that I'll be able to fit one in there. i'll report on my findings. i jsut hope I don't fry my lovely little Jornada.

Went to RadioShack and got a mono jack. Soldered wires to it. Put heatshrink tubing as a extra layer of protection over the cable. Now I just need to be able to access the speaker without breaking something. Thats what is holding me up.
Chris

The unit next to the headphone jack is a Noise filter.
Chris

hi Istvan (or István)

i can help you in learning hungarian if you'd like to

yes, i have the 728 battery for my 720 (and another one for my 728 ), capacity is 1960 mAh, that's why it's so great i have a normal 720 1500 mAh too and that lasts only 4-6 hours (worn out a little?).
the 680/690 has only 1100 mAh by default .. so 5 hours could be normal. or do you already have a higher capacity battery?

yeah that extended battery.. i was thinking of that.. but i already have many batteries (and rebuilding the 1500 one to 2400 mAh) so i don't need it. anyway you can get it from usedhandhelds.com for as little as 80$! maybe that helps