| Electronics > Repair |
| What more i can do? |
| << < (103/112) > >> |
| Swake:
In one of the pictures there is an issue with DRAM slot, see attached. I cannot say for sure if contact is made correctly or not. Certainly worth checking out in detail. |
| asis:
If it's "SIM 2" - next to CPU, then it's pin 70 of SIMM72 (FRAM). This is PD3 (Presense Detect) determining the full available FRAM volume, with all the ensuing consequences. - @Swake Please give the post number to view the content. |
| 222Lab_Test222:
It is indeed worth checking those Flash sticks BUT the problem still same. Why? Because in working board, when given 5v there is no beeping even if both flash and DRAM is removed. |
| 222Lab_Test222:
--- Quote from: asis on December 26, 2024, 06:43:40 am ---Ok. Let's leave it (1)... I'm just haunted by output pin 9 (MOSFET). What does it block? - You had SIM 1 strips with DRAM chips in other x 8 cases. - I don't rule out that in addition to the current date and time (IC23), Flash RAM (SIM2) is polled, where the profile of the current parameters of the power unit itself can be stored, i.e. the polling algorithm during initialization includes two consecutive stages. - Sorry, I made a mistake: DRAM - "SIM 1" FRAM - "SIM 2" --- End quote --- I am also still haunted by RTC things, the OP and TP is weird, all input as well as osc seems good, i even changed RTC still same issues. 8 cases /2 cases, all seems similar types of DRAM. I just think it is some version difference only. Here are images |
| Swake:
The issue is with the DRAM SIMM (not with the FRAM). From a datasheet this pin 70 is presence detect 4 (PD4). Nothing to do with addressing of data, this is used to provide size and speed information of the SIMM. --- Code: ---X = connected to GND o = open Pin 70 69 68 67 Size Speed ------------------------------------------------------ o o o o Free / Invalid o o o X 1 MB 120 ns o o X o 2 MB 120 ns o o X X 2 MB 70 ns o X o o 8 MB 70 ns o X o X 16 MB 70 ns o X X o 2 MB 80 ns On older machines o X X o 32 MB 70 ns On newer machines o X X X 8 MB 80 ns X o o o Reserved X o o X 1 MB 85 ns X o X o 2 MB 85 ns X o X X 4 MB 70 ns X X o o Reserved X X o X 1 MB 100 ns X X X o 2 MB 100 ns X X X X 4 MB 80 ns --- End code --- |
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