8088 won't go into turbo mode?

[Mike Chambers]

hey guys. my "PC's Limited" brand "TURBO-XT" is somehow stuck in 4.77 MHz mode. the jumper to go into turbo just doesn't seem to do anything. it used to work fine. i've checked all the jumpers and switches twice, but nothing is wrong there.

i just can't get it to go into 8 MHz mode. i have a switch hooked up to the jumper pins, and i run speed analysis software which shows no difference whatsoever when i have the switch on turbo. same when i pull the switch connector off the pins and just throw a jumper on in what should make it turbo mode.

has anybody ever seen or heard of anything like this?

 

[Amigaz]

Have the same trouble on a socket 3 motherboard which I've posted about here without any replies

 

[dongfeng]

Some Turbo boards allow you to change between turbo and non turbo modes using the keyboard. Something like Crtl Alt +/-.

 

[kb2syd]

Have you tried a different switch? It may be worn out or clogged with crud.

 

[Mike Chambers]

Some Turbo boards allow you to change between turbo and non turbo modes using the keyboard. Something like Crtl Alt +/-.

doesn't work on this one. it works on pins being jumpered/switched.

 

[Mike Chambers]

Have you tried a different switch? It may be worn out or clogged with crud.

even if that is the case, it still doesn't work when i use a plain ol' jumper.

 

[Yzzerdd]

Try using a different jumper, or even cleaning the contacts on the motherboard. The jumper you are using may be worn, or the contacts on the motherboard could be dirty.

--Jack

 

[barythrin]

Wow a PCs Limited (Anyone that doesn't know, that's before renaming the company to Dell)? cool.. been casually looking for one of those too.

Anyway, no I don't know how but I know on some early laptops I had it was ctrl+alt+h and ctrl+alt+L to switch.k

Just for kicks have you tried Dell's website? They *USED* to actually have those listed under support which I got a huge kick out of.

I just checked, they don't specify the system but they do have 3 8088 motherboards if you know what that one might have. http://support.dell.com/support/edocs/dta/ARC/00000005.htm#Switching Speed indicates atleast on this one it's ctrl+alt+- to change speeds and the only indicator is the turbo light on the front of the unit, no beeps, etc.

- John

 

[Mike Chambers]

yep, it's dell's first motherboard i believe. here is a picture of it installed in a case:

i did see 8088's on their site about a year ago, i'm going to take a look and see if i can find my board... the strange thing is though, it USED to work just fine using a jumper or switch..

 

[barythrin]

Yeah, let us know.

I guess if you're bored you might be able to trace the circuit that the jumper shorts and looks for any breaks in the line or circuitry on the way to the processor.

 

[Druid6900]

Could be that the crystal driving the 8MHz mode is bad.

 

[Terry Yager]

...or not getting power cauze sum'n else is bad?

--T

 

[Druid6900]

...or not getting power cauze sum'n else is bad?

--T

Like, say, a bad solder joint or some corrosion?

 

[Terry Yager]

Ummmn, yer the expert...I'm just the local rabble-rouser.

--T